A discussion of passives in the context of generalized phrase structure grammar (GPSG) looks at two problems associated with a lexical rule that derives passive participles from active verbs. The first occurs with sentences whose main verb takes an NP and does not have a passive counterpart. This situation requires a more restrictive metarule, and one is proposed. The second problem occurs with impersonal passives, illustrated in both English and Polish. While an analysis of impersonal passives can be provided within GPSG, it is seen as an unsatisfactory solution, and the government binding framework is suggested as a more appropriate approach. (MSE)