This pilot study investigated the feasibility of using functional magnetic resonance imaging (fMRI) as a physiological marker of brain plasticity before and after an intensive body-weight-supported treadmill training (BWSTT) program in children with cerebral palsy (CP). Six ambulatory children (four males, two females; mean age 10y 6mo, age range 6-14y) with spastic CP (four hemiplegia, two asymmetric diplegia, all Gross Motor Function Classification System Level I) received BWSTT twice daily for 2 weeks. All children tolerated therapy; only one therapy session was aborted due to fatigue. With training, over ground mean walking speed increased from 1.47 to 1.66m/s (p=0.035). There was no change in distance walked for 6 minutes (pre-: 451m; post-: 458m;p 0.851). In three children, reliable fMRIs were taken of cortical activation pre- and post-intervention. Post-intervention increases in cortical activation during ankle dorsiflexion were observed in all three children. This study demonstrates that children with CP between 6 and 14 years of age can tolerate intensive locomotor training and, with appropriate modifications, can complete an fMRI series. This study supports further studies designed to investigate training-dependent plasticity in children with CP.