Unintended population consequences of policies stem from three sources: (1) A policy overshoots its original goal; (2) different policies conflict, so that the implementation of one policy inhibits implementation of another policy; (3) negative consequences of a policy are unforeseen, or are anticipated but judged unlikely to be severe or considered less important than the positive aims of the policy. Examples from Singapore, South Africa, Italy, the U.S., and the former Soviet Union are discussed. © 2004 Human Sciences Press, Inc.