Thanks, Clint and Hans. This was the "best server" I had selected in Synaptic, and it's apparently outdated now:
$ sudo apt-cache policy php5-mysql php5-mysql: Installed: (none) Candidate: 5.3.6-11ubuntu1 Version table: 5.3.6-11ubuntu1 0 500 http://mirrors.ccs.neu.edu/ubuntu/ oneiric/main amd64 Packages Today the "best server" search yielded the following, which fixed my problem: $ sudo apt-cache policy php5-mysql php5-mysql: Installed: (none) Candidate: 5.3.6-13ubuntu3.2 Version table: 5.3.6-13ubuntu3.2 0 500 http://www.lug.bu.edu/mirror/ubuntu/ oneiric-updates/main amd64 Packages 500 http://www.lug.bu.edu/mirror/ubuntu/ oneiric-security/main amd64 Packages 5.3.6-13ubuntu3.1 0 500 http://www.lug.bu.edu/mirror/ubuntu/ oneiric/main amd64 Packages -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/886423 Title: Can't install php5-mysql in Ubuntu 11.10 due to unmet dependencies To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/php5/+bug/886423/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs