diff --git a/ChangeLog b/ChangeLog
index d89933fc4c..3bb2821a18 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+Thu Apr 15 22:33:35 2010  Yusuke Endoh  <mame@tsg.ne.jp>
+
+	* lib/uri/ftp.rb (URI::FTP#set_path): added to correct handling of
+	  special case where path of ftp is relative.  This converts relative
+	  path to absolute one, because external representation of ftp path is
+	  relative and internal representation is absolute.  [ruby-core:24077]
+
+	* lib/uri/ftp.rb (URI::FTP#initialize): converts absolute to relative.
+
+	* lib/uri/generic.rb (URI::Generic#check_path): allow relative path
+	  when scheme is ftp.
+
 Thu Apr 15 21:54:39 2010  Tanaka Akira  <akr@fsij.org>
 
 	* tool/file2lastrev.rb: use backtick for ruby 1.8.
diff --git a/lib/uri/ftp.rb b/lib/uri/ftp.rb
index 1ffd9090a6..4e33dadd33 100644
--- a/lib/uri/ftp.rb
+++ b/lib/uri/ftp.rb
@@ -118,12 +118,13 @@ module URI
     # +opaque+, +query+ and +fragment+, in that order.
     #
     def initialize(*arg)
+      arg[5] = arg[5].sub(/^\//,'').sub(/^%2F/,'/')
       super(*arg)
       @typecode = nil
       tmp = @path.index(TYPECODE_PREFIX)
       if tmp
         typecode = @path[tmp + TYPECODE_PREFIX.size..-1]
-        self.set_path(@path[0..tmp - 1])
+        @path = @path[0..tmp - 1]
 
         if arg[-1]
           self.typecode = typecode
@@ -185,6 +186,11 @@ module URI
       return @path.sub(/^\//,'').sub(/^%2F/,'/')
     end
 
+    def set_path(v)
+      super("/" + v.sub(/^\//, "%2F"))
+    end
+    protected :set_path
+
     def to_s
       save_path = nil
       if @typecode
diff --git a/lib/uri/generic.rb b/lib/uri/generic.rb
index 14ca97301b..4fdfd140fe 100644
--- a/lib/uri/generic.rb
+++ b/lib/uri/generic.rb
@@ -482,7 +482,9 @@ module URI
           "path conflicts with opaque"
       end
 
-      if @scheme
+      # If scheme is ftp, path may be relative.
+      # See RFC 1738 section 3.2.2, and RFC 2396.
+      if @scheme && @scheme != "ftp"
         if v && v != '' && parser.regexp[:ABS_PATH] !~ v
           raise InvalidComponentError,
             "bad component(expected absolute path component): #{v}"