diff --git a/src/constraints.jl b/src/constraints.jl
index 64c6e74655d..7c6d9309b7b 100644
--- a/src/constraints.jl
+++ b/src/constraints.jl
@@ -94,6 +94,10 @@ end
 
 _value_type(::Any, ::Any) = Any
 
+function _value_type(::ConstraintRef{M,<:MOI.ConstraintIndex{F}}) where {M,F}
+    return _value_type(M, F)
+end
+
 # Returns the value of MOI.ConstraintDualStart in a type-stable way
 function _dual_start(
     con_ref::ConstraintRef{M,MOI.ConstraintIndex{F,S}},
@@ -124,7 +128,7 @@ function set_dual_start_value(
         owner_model(con_ref),
         MOI.ConstraintDualStart(),
         con_ref,
-        vectorized_value,
+        _convert_if_something(_value_type(con_ref), vectorized_value),
     )
     return
 end
@@ -151,7 +155,8 @@ function set_dual_start_value(
     },
     value,
 )
-    MOI.set(owner_model(con_ref), MOI.ConstraintDualStart(), con_ref, value)
+    v = _convert_if_something(_value_type(con_ref), value)
+    MOI.set(owner_model(con_ref), MOI.ConstraintDualStart(), con_ref, v)
     return
 end
 
@@ -174,11 +179,12 @@ function set_start_value(
     },
     value,
 )
+    vectorized_value = vectorize(value, con_ref.shape)
     MOI.set(
         owner_model(con_ref),
         MOI.ConstraintPrimalStart(),
         con_ref,
-        vectorize(value, con_ref.shape),
+        _convert_if_something(_value_type(con_ref), vectorized_value),
     )
     return
 end
@@ -207,7 +213,8 @@ function set_start_value(
     },
     value,
 )
-    MOI.set(owner_model(con_ref), MOI.ConstraintPrimalStart(), con_ref, value)
+    v = _convert_if_something(_value_type(con_ref), value)
+    MOI.set(owner_model(con_ref), MOI.ConstraintPrimalStart(), con_ref, v)
     return
 end
 
diff --git a/test/test_constraint.jl b/test/test_constraint.jl
index 59c734d4865..20b43dab372 100644
--- a/test/test_constraint.jl
+++ b/test/test_constraint.jl
@@ -912,6 +912,7 @@ function test_dual_start()
     con = @constraint(model, 2x <= 1)
     @test dual_start_value(con) === nothing
     set_dual_start_value(con, 2)
+    @test MOI.get(model, MOI.ConstraintDualStart(), con) isa Float64
     @test dual_start_value(con) == 2.0
     set_dual_start_value(con, nothing)
     @test dual_start_value(con) === nothing
@@ -925,6 +926,9 @@ function test_dual_start_vector()
     @test dual_start_value(con_vec) === nothing
     set_dual_start_value(con_vec, [1.0, 3.0])
     @test dual_start_value(con_vec) == [1.0, 3.0]
+    set_dual_start_value(con_vec, [1, 3])
+    @test MOI.get(model, MOI.ConstraintDualStart(), con_vec) isa Vector{Float64}
+    @test dual_start_value(con_vec) == [1, 3]
     set_dual_start_value(con_vec, nothing)
     @test dual_start_value(con_vec) === nothing
     return
@@ -936,6 +940,7 @@ function test_primal_start()
     con = @constraint(model, 2x <= 1)
     @test start_value(con) === nothing
     set_start_value(con, 2)
+    @test MOI.get(model, MOI.ConstraintPrimalStart(), con) isa Float64
     @test start_value(con) == 2.0
     set_start_value(con, nothing)
     @test start_value(con) === nothing
@@ -949,6 +954,10 @@ function test_primal_start_vector()
     @test start_value(con_vec) === nothing
     set_start_value(con_vec, [1.0, 3.0])
     @test start_value(con_vec) == [1.0, 3.0]
+    set_start_value(con_vec, [1, 3])
+    attr = MOI.ConstraintPrimalStart()
+    @test MOI.get(model, attr, con_vec) isa Vector{Float64}
+    @test start_value(con_vec) == [1, 3]
     set_start_value(con_vec, nothing)
     @test start_value(con_vec) === nothing
     return