diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index db9944bb..6efdb8f4 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -12,7 +12,7 @@ jobs:
     strategy:
       matrix:
         run-on: [ 'ubuntu', 'macOS', 'windows' ]
-        go-version: [ 'oldstable', 'stable' ]
+        go-version: [ 'stable' ]
     name: Test
     runs-on: ${{ matrix.run-on }}-latest
     steps:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6feb987b..1f78e177 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
 
+### Removed
+
+- Remove konf.Logger in favor of slog (#48).
+
 ## [v0.2.0] - 3/18/2023
 
 ### Removed
diff --git a/config.go b/config.go
index f2a4afa9..cbe6aeba 100644
--- a/config.go
+++ b/config.go
@@ -7,6 +7,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"log/slog"
 	"strings"
 	"sync"
 
@@ -18,7 +19,6 @@ import (
 // Config is a registry which holds configuration loaded by Loader(s).
 type Config struct {
 	delimiter string
-	logger    Logger
 
 	values    map[string]any
 	providers []*provider
@@ -45,7 +45,7 @@ func New(opts ...Option) (*Config, error) {
 			return nil, fmt.Errorf("[konf] load configuration: %w", err)
 		}
 		maps.Merge(config.values, values)
-		config.logger.Info(
+		slog.Info(
 			"Configuration has been loaded.",
 			"loader", loader,
 		)
@@ -170,7 +170,7 @@ func (c *Config) Watch(ctx context.Context, fns ...func(*Config)) error { //noli
 					ctx,
 					func(values map[string]any) {
 						provider.values = values
-						c.logger.Info(
+						slog.Info(
 							"Configuration has been changed.",
 							"watcher", provider.watcher,
 						)
diff --git a/config_test.go b/config_test.go
index cf1905b3..fb24c5e2 100644
--- a/config_test.go
+++ b/config_test.go
@@ -254,25 +254,3 @@ type errorLoader struct{}
 func (errorLoader) Load() (map[string]any, error) {
 	return nil, errors.New("load error")
 }
-
-func TestConfig_logger(t *testing.T) {
-	t.Parallel()
-
-	logger := &logger{}
-	_, err := konf.New(konf.WithLogger(logger), konf.WithLoader(mapLoader{}))
-	require.NoError(t, err)
-
-	require.Equal(t, "Configuration has been loaded.", logger.message)
-	require.Equal(t, []any{"loader", mapLoader{"configured": true}}, logger.keyAndValues)
-}
-
-type logger struct {
-	konf.Logger
-	message      string
-	keyAndValues []any
-}
-
-func (l *logger) Info(message string, keyAndValues ...any) {
-	l.message = message
-	l.keyAndValues = keyAndValues
-}
diff --git a/global.go b/global.go
index c7c3b0aa..e254c12a 100644
--- a/global.go
+++ b/global.go
@@ -5,6 +5,7 @@ package konf
 
 import (
 	"context"
+	"log/slog"
 	"reflect"
 	"sync"
 
@@ -21,9 +22,9 @@ func Get[T any](path string) T { //nolint:ireturn
 
 	var value T
 	if err := global.Unmarshal(path, &value); err != nil {
-		global.logger.Error(
+		slog.Error(
 			"Could not read config, return empty value instead.",
-			err,
+			"error", err,
 			"path", path,
 			"type", reflect.TypeOf(value),
 		)
diff --git a/global_test.go b/global_test.go
index a8ed1fa9..dbf49981 100644
--- a/global_test.go
+++ b/global_test.go
@@ -47,8 +47,8 @@ func TestGet_error(t *testing.T) {
 	log.SetFlags(0)
 
 	require.False(t, konf.Get[bool]("config"))
-	expected := "Error Could not read config, return empty value instead." +
-		" error=[konf] decode: cannot parse '' as bool: strconv.ParseBool: parsing \"string\": invalid syntax" +
+	expected := "ERROR Could not read config, return empty value instead." +
+		" error=\"[konf] decode: cannot parse '' as bool: strconv.ParseBool: parsing \\\"string\\\": invalid syntax\"" +
 		" path=config type=bool\n"
 	require.Equal(t, expected, buf.String())
 }
diff --git a/go.mod b/go.mod
index b315a597..dd34f9c1 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module github.com/ktong/konf
 
-go 1.20
+go 1.21
 
 require (
 	github.com/fsnotify/fsnotify v1.7.0
diff --git a/logger.go b/logger.go
deleted file mode 100644
index b92c8b26..00000000
--- a/logger.go
+++ /dev/null
@@ -1,43 +0,0 @@
-// Copyright (c) 2023 The konf authors
-// Use of this source code is governed by a MIT license found in the LICENSE file.
-
-package konf
-
-import (
-	"bytes"
-	"fmt"
-	"log"
-)
-
-// Logger is the interface that wraps the basic methods for logging.
-type Logger interface {
-	Info(message string, keyAndValues ...any)
-	Error(message string, err error, keyAndValues ...any)
-}
-
-type stdlog struct{}
-
-func (l stdlog) Info(message string, keyAndValues ...any) {
-	l.log("Info", message, keyAndValues...)
-}
-
-func (l stdlog) Error(message string, err error, keyAndValues ...any) {
-	if err != nil {
-		keyAndValues = append([]any{"error", err.Error()}, keyAndValues...)
-	}
-
-	l.log("Error", message, keyAndValues...)
-}
-
-func (stdlog) log(level, message string, keyAndValues ...any) {
-	buf := new(bytes.Buffer)
-	buf.WriteString(level)
-	buf.WriteRune(' ')
-	buf.WriteString(message)
-	for i := 0; i < len(keyAndValues); i += 2 {
-		buf.WriteRune(' ')
-		buf.WriteString(fmt.Sprintf("%s=%v", keyAndValues[i], keyAndValues[i+1]))
-	}
-
-	log.Print(buf)
-}
diff --git a/option.go b/option.go
index 156efac4..f0dc673c 100644
--- a/option.go
+++ b/option.go
@@ -22,15 +22,6 @@ func WithDelimiter(delimiter string) Option {
 	}
 }
 
-// WithLogger provides a Logger implementation to logger.
-//
-// The default implementation is using standard [log].
-func WithLogger(logger Logger) Option {
-	return func(config *options) {
-		config.logger = logger
-	}
-}
-
 // Option configures the given Config.
 type Option func(*options)
 
@@ -44,7 +35,6 @@ func apply(opts []Option) options {
 	option := &options{
 		Config: &Config{
 			delimiter: ".",
-			logger:    stdlog{},
 			values:    make(map[string]any),
 		},
 	}
diff --git a/provider/file/file.go b/provider/file/file.go
index a305872e..f3616983 100644
--- a/provider/file/file.go
+++ b/provider/file/file.go
@@ -17,7 +17,7 @@ package file
 import (
 	"fmt"
 	"io/fs"
-	"log"
+	"log/slog"
 	"os"
 )
 
@@ -47,7 +47,7 @@ func (f File) Load() (map[string]any, error) {
 	}
 	if err != nil {
 		if f.ignoreNotExist && os.IsNotExist(err) {
-			log.Printf("Config file %s does not exist.", f.path)
+			slog.Warn("Config file does not exist.", "file", f.path)
 
 			return make(map[string]any), nil
 		}
diff --git a/provider/file/file_test.go b/provider/file/file_test.go
index 723c34bd..5731e198 100644
--- a/provider/file/file_test.go
+++ b/provider/file/file_test.go
@@ -6,11 +6,9 @@
 package file_test
 
 import (
-	"bytes"
 	"context"
 	"errors"
 	"io/fs"
-	"log"
 	"os"
 	"path/filepath"
 	"strings"
@@ -122,20 +120,6 @@ func TestFile_Load(t *testing.T) {
 	}
 }
 
-func TestFile_log(t *testing.T) {
-	buf := new(bytes.Buffer)
-	log.SetOutput(buf)
-	log.SetFlags(0)
-
-	_, err := file.New(
-		"not_found.json",
-		file.IgnoreFileNotExit(),
-	).Load()
-
-	require.NoError(t, err)
-	require.Equal(t, "Config file not_found.json does not exist.\n", buf.String())
-}
-
 func TestFile_Watch(t *testing.T) {
 	testcases := []struct {
 		description string
diff --git a/provider/file/watch.go b/provider/file/watch.go
index 82abf5ac..45168c8f 100644
--- a/provider/file/watch.go
+++ b/provider/file/watch.go
@@ -8,7 +8,7 @@ package file
 import (
 	"context"
 	"fmt"
-	"log"
+	"log/slog"
 	"path/filepath"
 	"time"
 
@@ -26,7 +26,7 @@ func (f File) Watch(ctx context.Context, watchFunc func(map[string]any)) error {
 	}
 	defer func() {
 		if err := watcher.Close(); err != nil {
-			log.Printf("Error when closing watcher for %s: %v", f.path, err)
+			slog.Error("Error when closing file watcher.", "file", f.path, "error", err)
 		}
 	}()
 
@@ -73,12 +73,12 @@ func (f File) Watch(ctx context.Context, watchFunc func(map[string]any)) error {
 
 			switch {
 			case event.Has(fsnotify.Remove):
-				log.Printf("Config file %s has been removed.", f.path)
+				slog.Warn("Config file has been removed.", "file", f.path)
 				watchFunc(nil)
 			case event.Has(fsnotify.Create) || event.Has(fsnotify.Write):
 				values, err := f.Load()
 				if err != nil {
-					log.Printf("Error when reloading configuration from %s: %v", f.path, err)
+					slog.Error("Error when reloading config file", "file", f.path, "error", err)
 
 					continue
 				}
@@ -90,7 +90,7 @@ func (f File) Watch(ctx context.Context, watchFunc func(map[string]any)) error {
 				return nil
 			}
 
-			log.Printf("Error when watching file %s: %v", f.path, err)
+			slog.Error("Error when watching file", "file", f.path, "error", err)
 
 		case <-ctx.Done():
 			return nil
diff --git a/provider/file/watch_unsupported.go b/provider/file/watch_unsupported.go
index 618cb06b..c72ef6b0 100644
--- a/provider/file/watch_unsupported.go
+++ b/provider/file/watch_unsupported.go
@@ -7,12 +7,12 @@ package file
 
 import (
 	"context"
-	"log"
+	"log/slog"
 	"runtime"
 )
 
 func (f File) Watch(context.Context, func(map[string]any)) error {
-	log.Printf("File.Watch does not supported on %s.", runtime.GOOS)
+	slog.Warn("File.Watch does not supported on runtime.", "runtime", runtime.GOOS)
 
 	return nil
 }