assuming its a home network, and assuming there both running class C subnets (225.225.225.0), try changing the subnet of the 2nd router... like this i guess
ADSL --- router 1 --- router 2
(192.168.1.1) (192.168.2.1)
reboot and run a pathping and traceroute on a client machine (assuming your using windows :P 2000/xp), also assuming your using DHCP (which i guess you'd have to be unless your net connection was static) check the DHCP servers are enabled, it'd help if you posted the TCP/IP setups so we could get a better insight as to what and where the problem lies :)
of course if your connecting two routers to the same line, that wont work because the lines taken up by the first connected router, you would have to have a setup very similar to the one i mentioned above to share one phoneline/ADSL-link between two subnets