diff --git a/lib/matrix.rb b/lib/matrix.rb
index 390aaf6..8ee6354 100644
--- a/lib/matrix.rb
+++ b/lib/matrix.rb
@@ -60,6 +60,8 @@ end
 # * #minor(*param)
 # * #first_minor(row, column)
 # * #cofactor(row, column)
+# * #row_merge(*matrices)
+# * #merge(*matrices)
 # * #column_merge(*matrices)
 #
 # Properties of a matrix:
@@ -638,6 +640,21 @@ class Matrix
   end
 
   #
+  # Merge matrices between rows.
+  #
+  #   Matrix[[1, 2], [3, 4]].row_merge(Matrix[[5], [6]])
+  #     => 1 2 5
+  #        3 4 6
+  #
+  def row_merge(*matrices)
+    if matrices.any?{|m| m.row_size != row_size}
+      raise ErrDimensionMismatch, "all matrices should have same row size"
+    end
+    transpose.column_merge(*matrices.map(&:transpose)).transpose
+  end
+  alias_method :merge, :row_merge
+
+  #
   # Merge matrices between column vertically.
   #
   #   Matrix[[1, 2], [3, 4]].column_merge(Matrix[[5, 6]])