Stroke is a leading cause of death and disability in the USA. Up to 60% of patients do not fully recover despite intensive physical therapy treatment.N-Methyl-D-aspartate receptors(NMDA-R) have been shown to play a role in synaptic plasticitywhen activated. D-Cycloserine promotes NMDA receptor function by binding to receptors with unoccupied glycine sites. These receptors are involved in learning and memory.We hypothesized thatD-cycloserine,when combined with robotic-assisted physiotherapy (RAP), would result in greater gains compared with placebo + RAP in stroke survivors. Participants (𝑛 = 14) were randomized to Dcycloserine plus RAP or placebo plus RAP. Functional, cognitive, and quality-of-life measures were used to assess recovery. There was significant improvement in grip strength of the affected hand within both groups from baseline to 3 weeks (95% confidence interval for mean change, 3.95 ± 2.96 to 4.90 ± 3.56N for D-cycloserine and 5.72 ± 3.98 to 8.44 ± 4.90N for control). SIS mood domain showed improvement for both groups (95% confidence interval for mean change, 72.6 ± 16.3 to 82.9 ± 10.9 forD-cycloserine and 82.9 ± 13.5 to 90.3 ± 9.9 for control).This preliminary study does not provide evidence that D-cycloserine can provide greater gains in learning compared with placebo for stroke survivors.