Students with mild mental retardation (MMR) often demonstrate reluctance, confusion, or performance deterioration when required to perform tasks that require looking, reaching, or stepping across the body’s midline. Sensory integration theorists contend that midline crossing is a predictor of bilateral integration. However, in factor analysis studies, very little variance is accounted for by midline crossing data. The present study viewed midline crossing as a function of information processing and utilized a temporal assessment process rather than the usual spatial assessment process. Results indicated that subjects classified as MMR experienced slower choice reaction time (CRT) and movement time (MT) for stimuli placed across the body’s midline. However, higher functioning subjects with MMR performed equally well on CRT for ipsilateral and crosslateral tasks. The data provide evidence for a developmental hypothesis as an explanation for midline crossing problems.