The trend is increasing to incorporate assessments of abundance into surveys for immatureAedes aegypti to identify the most important types of containers that should be targeted for control. In this study,we examined whether funnel traps could be used to sample immature Ae. aegypti from water storage jars rangingin size from 0.28-m diameter (30 liters) to 0.52-m diameter (150 liters). The effects of jar size and duration offunnel trap sampling were investigated and a set of calibration factors was developed to convert funnel trapnumbers to absolute population estimates (0.28-m diameter = 2.5, 0.38-m diameter : 3.0, 0.4g-m diameter =4.6, and 0.52-m diameter = 7.4). Although the funnel traps were highly sensitive (90-100%) for detectingimmature Ae. aegypti at densities as low as 25 3rd and 4th instars per jar, the large variation in funnel traprecapture rates meant that absolute population estimates based on a single funnel trap sample were inaccurate.However, by using a computer simulation, estimates of the total overall numbers of larvae from multiple iarswere reasonably accurate (+/-20%), if more than 50 positive jars were surveyed. For example, 95% confidenceintervals for the percentage elTor in estimated numbers of immatures from i series of 50 0.38-m-diameter and50 0.52-m-diameter jars, were - 10.0% to +10.2% and -l9.9% to -17.8%, respectively. Although we generallyrecommend the use of nets to sample immature Ae. aegypti in jars, under some conditions funnel traps may bemore acceptable than nets, because some householders object to the increased turbidity associated with netsampling in jars.