The Sternberg Memory Scanning task was used to test the hypotheses that immediate working memory (WM) would be impaired during moderate rising blood alcohol concentrations (BACs), and provision of a rewarding incentive for good performance under alcohol would counteract this impairment. Two groups (n=18) of social drinkers received either 0.62 g/kg alcohol (A) or a placebo (P). Reward (verbal feedback and money) for good performance was provided to another pair of alcohol and placebo groups (n=18) (AR and PR). All participants completed two tests when BACs in the alcohol groups were rising (68 and 80 mg/100 ml) and two tests during declining BACs (73 and 64 mg/100 ml). Comparisons of A and P groups showed that rising BACs impaired immediate WM [increased errors, slowed rate of mental scanning, slowed reaction time (RT) when a larger number of items had to be held in WM]. Comparisons of AR and PR groups showed that reward for good performance during rising BACs counteracted impairment in scanning rate and RT but did not reduce errors. Tests during declining BACs of 73 mg/100 ml indicated some symptoms of impairment abated before others. When BAC declined to 64 mg/106 ml, the groups no longer differed on any measure of WM. An acute dose of alcohol can impair aspects of immediate WM performance while BACs are rising, and some of these effects can be reversed when incentives to perform well are provided.