We present the results of a spectroscopic study of planetary nebulae (PN) in the Magellanic Clouds. The optical survey of He, N, O, and Ne abundances by Monk et al. (1988) has been updated by higher S/N AAT optical data. In addition, carbon and other elemental abundances have been derived from the IUE spectra of 40 PN. Ionized nebular masses have been derived for 80 PN. The ionised mass versus nebular electron density plot shows that planetary nebulae become optically thin when their electron densities drop below 4500 cm−3. Below this density, the mean nebular hydrogen mass found for non-Type I PN is 0.22±0.08 M⊙. Using Zanstra and energy-balance methods, the mean central star mass found for 14 SMC and LMC PN is 0.59±0.02 M⊙.