This study investigated second language (L2) learners' acquisition of English /t, d/ deletion patterns in word-final consonant clusters, (a) focusing on how constraints such as grammatical conditioning and phonological environment affect deletion of /t, d/ in L2 acquisition and (b) determining the extent to which these L2 learners had acquired native-speaker-like patterns of deletion in ways that may be similar to patterns attested for first and second language acquisition in previous research. Seven native speakers of Mandarin Chinese, all graduate students at a Midwestern university in the United States, participated in the study. Findings indicate that the participants had not yet acquired targetlike use of /-t, -d/ deletion patterns for all constraints. Following the linguistic environment, possibly due to the influence of sonority, appeared to be the easiest constraint to acquire. Other linguistic constraints, such as preceding linguistic environment and grammatical conditioning, appeared to be more difficult to acquire, probably due to the effects of first language transfer.