Background. Transcranial direct current stimulation (tDCS) is a form of noninvasive brain stimulation that has shown improved adult stroke outcomes. Applying tDCS in children with congenital hemiparesis has not yet been explored. Objective. The primary objective of this study was to explore the safety and feasibility of single-session tDCS through an adverse events profile and symptom assessment within a double-blind, randomized placebo-controlled preliminary study in children with congenital hemiparesis. A secondary objective was to assess the stability of hand and cognitive function. Design. A double-blind, randomized placebo-controlled pretest/posttest?follow-up study was conducted. Setting. The study was conducted in a university pediatric research laboratory. Participants. Thirteen children, ages 7 to 18 years, with congenital hemiparesis participated. Measurements. Adverse events/safety assessment and hand function were measured. Intervention. Participants were randomly assigned to either an intervention group or a control group, with safety and functional assessments at pretest, at posttest on the same day, and at a 1-week follow-up session. An intervention of 10 minutes of 0.7 mA tDCS was applied to bilateral primary motor cortices. The tDCS intervention was considered safe if there was no individual decline of 25% or group decline of 2 standard deviations for motor evoked potentials (MEPs) and behavioral data and no report of adverse events. Results. No major adverse events were found, including no seizures. Two participants did not complete the study due to lack of MEP and discomfort. For the 11 participants who completed the study, group differences in MEPs and behavioral data did not exceed 2 standard deviations in those who received the tDCS (n=5) and those in the control group (n=6). The study was completed without the need for stopping per medical monitor and biostatisticial analysis. Limitations. A limitation of the study was the small sample size, with data available for 11 participants. Conclusions. Based on the results of this study, tDCS appears to be safe, feasible, and well tolerated in most children with hemiparesis. Future investigations of serial sessions of tDCS in conjunction with rehabilitation in pediatric hemiparesis are indicated to explore the benefit of a synergistic approach to improving hand function.