Cross-linguistically, languages allow a wider variety of phonotactic patterns in onsets than in codas. However, the variability of phonotactic patterns in coda position in different languages suggests these patterns must, at least in part, be learned. Two experiments were conducted to explore whether there is an asymmetry in English-learning infants' ability to learn novel phonotactic patterns in word-medial onset and coda positions. In Experiment 1, English-learning 8- and 12-month-olds were familiarized with bisyllabic nonsense words with voiced fricatives restricted to either word-medial onset (Onset condition) or word-medial coda positions (Coda condition). At test, infants heard novel words that either followed or violated the familiarized patterns. Twelve-month-olds in the Onset condition showed a preference for the familiarized pattern; however, 12-month-olds in Coda condition as well as 8-month-olds in both conditions displayed no such preference. To explore whether there is a developmental pattern in these positional effects, in Experiment 2, 15-month-olds were tested in only the Coda condition. These toddlers showed a preference for the familiarized phonotactic pattern. These findings support the hypothesis that infants' learning of positional phonotactics is asymmetrical.