Solar collecting area is one of the most important operating parameters of active solar stills. No experimental work has been performed to investigate the effect of this parameter to date. Furthermore in all of previous theoretical studies the effect of solar collecting area was examined during only the first 24-hour period of the operation of stills with one specified brine depth. However the present work experimentally studies the long-term simultaneous effects of collector area and brine depth on the performance of active solar stills. For this purpose four parallel active solar stills with different collector areas were fabricated and experiments were conducted for 5 consecutive days during which different amounts of brine depth were considered for active solar stills. The present results indicated that the overall trend of distilled water production and efficiency lessened with decreased brine depth for all solar collecting areas. Moreover, as the solar collecting area increased, water production of stills increased but their efficiency decreased for all brine depths. Furthermore the current results showed that for active solar stills with low brine depth and high solar collecting area the brine may boil and this boiling decreases the efficiency of active solar stills. (C) 2014 Elsevier B.V. All rights reserved.