Mild traumatic brain injury (MTBI) is associated with cognitive,affective, and physical sequelae. When symptoms persist for more than 3 months, a diagnosis of Post-Concussion Syndrome (PCS) is often given. The current study tracked symptom development to explore the natural sequelae of MTBI. Twenty-six MTBI patients received a comprehensive neuropsychological assessment at three intervals: within 1 week, at 4 months and at 7 months post-concussion. Based on DSMIV criteria and clinical judgment, two external raters diagnosed five MTBI participants with PCS. Results suggested that aspects of cognitive functioning of the symptomatic MTBI (i.e., PCS) participants were different from matched normal control (NC) subjects, and from the 21 MTBI patients who were asymptomatic, at 4 months. Asymptomatic MTBI participants improved in overall level of functioning from 4 to 7 months, but remained significantly different from NC participants in their reduced verbal fluency and working memory functioning.