Phonemic categorization is the ability to discriminate and organize speech sounds into categories. This ability begins soon after birth and continues to refine as an individual matures. An association between categorical labeling and phonological awareness has been reported. A strong link between perception and production has been established. The present study examined phonemic categorization of two groups of four listeners. Eight-to ten-year-old children with an articulation disorder were compared with typically speaking peers to determine if the two groups differed in their ability to categorize speech sounds. Behavioral and electrophysiological measures were used to ascertain if any differences existed. These measures were obtained in response to four stimulus pairs (/pɑ/-/tɑ/, /tɑ/-/kɑ/, /pɑ/-/kɑ/, /sɑ/-/ʃɑ/). Three of the pairs (/pɑ/-/tɑ/, /tɑ/-/kɑ/, /pɑ/-/kɑ/) differed by place of articulation only and the fourth pair (/sɑ/-/ʃɑ/) consisted of sounds that are more commonly found in error for the age group of the participants. Behavioral data showed differences in reaction time between the two groups as well as between correct and incorrect responses. Electrophysiological data including the mismatch negativity showed that both groups perceived a distinction between the stimuli presented, but the normal control group generally displayed a higher SD for peak latency and amplitude. The normal control group also generally displayed a higher mean amplitude. These results suggest a difference between the two groups in the underlying processes of phonemic categorization. Specifically, these results support that the normal control group's ability to distinguish and categorize speech sounds is better established than that of their peers with an articulation disorder.