Sediment transport capacity is an important control on soil erosion and deposition by overland flow. To investigate the controls of transport capacity in laminar interrill overland flow on stone-covered surfaces, 357 flume experiments were performed using a single sediment size. Multiple regression analyses reveal that transport capacity is positively related to excess flow power &ohgr;-&ohgr;c, but the slope of the relation is steeper where &ohgr;<0.3 W m-2 than where &ohgr;≥0.3 W m-2. Transport capacity is positively related to rainfall intensity where &ohgr;<0.3 W m-2 and negatively related to rainfall intensity where &ohgr;≥0.3 W m-2. Transport capacity is negatively related to stone concentration and positively related to stone size irrespective of the value of &ohgr;. Finally, transport capacity is negatively related to fluid viscosity where &ohgr;<0.3 W m-2 and unrelated to viscosity where &ohgr;≥0.3 W m-2. ¿ 1999 American Geophysical Union