note grizzley So if that's acceptable for you - use while loop to determine max amount of occurences. There will be no more than length / 2 occurences, so start with this max value and decrease it while trying to match: <code> $x = "abcdefgxxabcdefgzzabcdsjfhkdfab"; $len=int(length($x)/2); while($x !~ /(\w{2,})(.*?\1){$len}/) { $len-- }; $x =~ /(\w{2,})(.*?\1){$len}/; # 'strange line' print $1 </code> (to self: do not know why I have to add 'strange line', without it nothing is printed, but $len is correctly set to 4) <p>I tried to generate the list and include it in one regexp: <code> $ perl -le '$x = "abcdefgxxabcdefgzzabcdsjfhkdfab"; $len=int(length($x)/2); $restring = join"|", map {"(?:.*?\\1){$_}"} reverse(1..$len); print $restring; print $1 if $x =~ /(\w{2,})($restring)/;' (?:.*?\1){15}|(?:.*?\1){14}|(?:.*?\1){13}|(?:.*?\1){12}|(?:.*?\1){11}|(?:.*?\1){10}|(?:.*?\1){9}|(?:.*?\1){8}|(?:.*?\1){7}|(?:.*?\1){6}|(?:.*?\1){5}|(?:.*?\1){4}|(?:.*?\1){3}|(?:.*?\1){2}|(?:.*?\1){1} abcdefg </code> but it does not work as expected (probably some stupid mistake, maybe someone else can tell what's wrong with it). 998200 998223