The purpose of the present study was to determine if vocabulary knowledge is related to degree of hearing loss. A 50-question multiple-choice vocabulary test comprised of old and new words was administered to 43 adults with hearing loss (19 to 92 years old) and 51 adults with normal hearing (20 to 40 years old). Degree of hearing loss ranged from mild to moderately-severe as determined by bilateral pure-tone thresholds. Education levels ranged from some high school to graduate degrees. It was predicted that knowledge of new words would decrease with increasing hearing loss, whereas knowledge of old words would be unaffected. The Test of Contemporary Vocabulary (TCV) was developed for this study and contained words with old and new definitions. The vocabulary scores were subjected to repeated-measures ANOVA with definition type (old and new) as the within-subjects factor. Hearing level and education were between-subjects factors, while age was entered as a covariate. The results revealed no main effect of age or education level, while a significant main effect of hearing level was observed. Specifically, performance for new words decreased significantly as degree of hearing loss increased. A similar effect was not observed for old words. These results indicate that knowledge of new definitions is inversely related to degree of hearing loss.