We present our analysis of the UV spectra of the fast ONeMg Nova LMC 1990#1. Observations with the IUE began on 1990 January 18 and continued through to 1990 March 15. We have analysed these spectra, and determined line fluxes and physical parameters as a function of time. Using both He ii lines and the Balmer decrement, we find the reddening for the nova to be E(B−V)≃0.22. Using the photoionization code cloudy 90.03b and the minimization routine minuit, we derive elemental abundances for the ejecta. We find the following abundances, relative to solar material: He=1, C=8, N=109, O=20, Ne=62, Mg=16, Al=257 and Si=41. These results are based on independent fits to different data sets acquired three weeks apart. These abundances are extremely similar to those found for V693 Corona Austrinae 1981. Given the position of V693 CrA in the Galaxy and the range of distances found for it, the similar abundances imply that the V693 CrA outburst took place on an older population white dwarf. The high N/O ratio implies an outburst on a massive white dwarf.