Index: test/testBigDecimal.rb
===================================================================
--- test/testBigDecimal.rb	(revision 5172)
+++ test/testBigDecimal.rb	(working copy)
@@ -142,6 +142,13 @@
 test_equal 1.0-one, 0.0
 
 test_equal("1.0", BigDecimal.new('1.0').to_s('F'))
+test_equal("0.1", BigDecimal.new('0.1').to_s('F'))
+test_equal("0.1", BigDecimal.new('.1').to_s('F'))
+test_equal("0.001", BigDecimal.new('.001').to_s('F'))
+test_equal("0.001", BigDecimal.new('.001').to_s('F'))
+test_equal("0.1", BigDecimal.new('.1').to_s('F'))
+test_equal("1.0", BigDecimal.new('1.').to_s('F'))
+test_equal("1.0", BigDecimal.new('1').to_s('F'))
 test_equal("0.0", BigDecimal.new('0.0').to_s)
 
 test_equal(BigDecimal("2"), BigDecimal("1.5").round)
Index: src/org/jruby/RubyBigDecimal.java
===================================================================
--- src/org/jruby/RubyBigDecimal.java	(revision 5172)
+++ src/org/jruby/RubyBigDecimal.java	(working copy)
@@ -684,7 +684,7 @@
                 String s = removeTrailingZeroes(unscaled);
                 if("".equals(s)) {
                     build.append("0");
-            } else {
+                } else {
                     build.append(s);
                 }
             } else {
@@ -703,13 +703,16 @@
             build.append("E").append(exponent);
             out = build.toString();
         } else {
-            int ix = abs.toString().indexOf('.');
-            String whole = unscaled;
-            String after = null;
-            if(ix != -1) {
-                whole = unscaled.substring(0,ix);
-                after = unscaled.substring(ix);
+            String values[] = abs.toString().split("\\.");
+            String whole = "0";
+            if (values.length > 0) {
+                whole = values[0];
             }
+            String after = "0";
+            if (values.length > 1) {
+                after = values[1];
+            }
+            
             int signum = value.signum();
             StringBuffer build = new StringBuffer();
             build.append(signum == -1 ? "-" : (signum == 1 ? (pos_sign ? (pos_space ? " " : "+" ) : "") : ""));