In Newfoundland, the American lobster (Homarus americanus) fishery has considerable socioeconomic value. Concern about the sustainability of this fishery continues to be a concern as a result of high exploitation rates. Conservation initiatives (marine protected areas, a slot fishery, and v-notching) have been established in several lobster fishing areas (LFAs) in western Newfoundland to increase the number of large lobsters and fecundity (egg production) of populations. However, there has been concern by harvesters in western Newfoundland, where slot fisheries are in effect, that the large lobsters being caught are rarely ovigerous.We used extensive field data from 5 LFAs in western Newfoundland (LFA12, LFA13A, LFA13B, LFA14A, and LFA14B) to test whether the spawning odds depend on size in a slot fishery, where large females were present in sufficient numbers to allow reliable estimates. Three analyses of size-dependent spawning odds were conducted via logistic regression: 2 analyses by year for LFA14A and LFA14B from 2006 to 2011 and 1 spatial analysis for 5 LFAs (LFA12, 13A, 13B, 14A, and 14B) during the same year (2010). In 4 of 6 y, for both LFA14A and LFA14B, spawning odds increased with size, and for 3 of the 5 LFAs for the same year, spawning odds increased with size. We found no evidence of a decrease in spawning odds with size and, equivalently, no decrease in percent ovigerous with increasing size. Our results support the use of spawning odds to calculate the effects of sustainability measures in lobsters.