The results of four attempts at yearly intervals to estimate populations of Amolops lamtensis (Blgr.) along 360 m of forest stream are discussed and the most consistent estimates are obtained using Jolly's (1965) method of analysing such data. Observations of movement within the population indicate that most frogs are recaptured close to the original point of capture although a few show considerable downstream movement, possibly as a result of being swept away by the current. The recapture expectations are not, however, random and there is a strong indication that larger frogs are more liable to recapture. There is also evidence that frogs are available for recapture for different lengths of time, and it is likely that this leads to an under-estimate of the total population.