Refrigerant R-410a flow distribution is experimentally studied in a test section simulating a minichannel heat exchanger having vertical headers with two pass configuration. Tubes are heated to yield a test section outlet superheat of 5 degrees C with inlet quality of 0.3. Mass flux is varied from 60kg/m(2)-s to 70kg/m(2)-s. Effects of outlet locations are investigated in a search for an optimum configuration. The effect of varying the number of tubes of each pass is also investigated. Results show that significant liquid flows through bottom channels, and less liquid is supplied to top channels. For the outlet location, a bottom outlet is better than a middle or top outlet. In addition, assigning a lower number of tubes to inlet pass yields better flow distribution. Correlations are developed for the fraction of liquid or gas taken off by the downstream channel as a function of header gas Reynolds number immediately upstream. The correlations may be used to predict the liquid or gas distribution in a parallel-flow heat exchanger havin vertical headers.