diff --git a/R/diagonalNetwork.R b/R/diagonalNetwork.R
index 638d1111..c0107574 100644
--- a/R/diagonalNetwork.R
+++ b/R/diagonalNetwork.R
@@ -6,6 +6,8 @@
 #' @param width numeric width for the network graph's frame area in pixels (if
 #'   \code{NULL} then width is automatically determined based on context)
 #' @param fontSize numeric font size in pixels for the node text labels.
+#' @param fontSizeTransition numeric font size in pixels for the node text
+#'  labels after mouseover transition is complete.
 #' @param fontFamily font family for the node text labels.
 #' @param linkColour character string specifying the colour you want the link
 #' lines to be. Multiple formats supported (e.g. hexadecimal).
@@ -92,6 +94,7 @@ diagonalNetwork <- function(
                           height = NULL,
                           width = NULL,
                           fontSize = 10,
+                          fontSizeTransition = 25,
                           fontFamily = "serif",
                           linkColour = "#ccc",
                           nodeColour = "#fff",
@@ -112,6 +115,7 @@ diagonalNetwork <- function(
         height = height,
         width = width,
         fontSize = fontSize,
+        fontSizeTransition = fontSizeTransition,
         fontFamily = fontFamily,
         linkColour = linkColour,
         nodeColour = nodeColour,
diff --git a/inst/htmlwidgets/diagonalNetwork.js b/inst/htmlwidgets/diagonalNetwork.js
index b7b5db5d..fda24dff 100755
--- a/inst/htmlwidgets/diagonalNetwork.js
+++ b/inst/htmlwidgets/diagonalNetwork.js
@@ -169,7 +169,7 @@ HTMLWidgets.widget({
       d3.select(this).select("text").transition()
         .duration(750)
         .style("stroke-width", ".5px")
-        .style("font", "25px " + x.options.fontFamily)
+        .style("font", x.options.fontSizeTransition + "px " + x.options.fontFamily)
         .style("opacity", 1);
     }
 
diff --git a/man/diagonalNetwork.Rd b/man/diagonalNetwork.Rd
index 2bc47050..71f487ed 100644
--- a/man/diagonalNetwork.Rd
+++ b/man/diagonalNetwork.Rd
@@ -10,10 +10,20 @@ IEEE Transactions on Software Engineering, SE-7(2), 223-228.
 Mike Bostock: \url{http://bl.ocks.org/mbostock/4339083}.
 }
 \usage{
-diagonalNetwork(List, height = NULL, width = NULL, fontSize = 10,
-  fontFamily = "serif", linkColour = "#ccc", nodeColour = "#fff",
-  nodeStroke = "steelblue", textColour = "#111", opacity = 0.9,
-  margin = NULL)
+diagonalNetwork(
+  List,
+  height = NULL,
+  width = NULL,
+  fontSize = 10,
+  fontSizeTransition = 25,
+  fontFamily = "serif",
+  linkColour = "#ccc",
+  nodeColour = "#fff",
+  nodeStroke = "steelblue",
+  textColour = "#111",
+  opacity = 0.9,
+  margin = NULL
+)
 }
 \arguments{
 \item{List}{a hierarchical list object with a root node and children.}
@@ -26,6 +36,9 @@ diagonalNetwork(List, height = NULL, width = NULL, fontSize = 10,
 
 \item{fontSize}{numeric font size in pixels for the node text labels.}
 
+\item{fontSizeTransition}{numeric font size in pixels for the node text
+labels after mouseover transition is complete.}
+
 \item{fontFamily}{font family for the node text labels.}
 
 \item{linkColour}{character string specifying the colour you want the link