This study compared the effectiveness of a web-based physical activity intervention to two control conditions in terms of increasing walking behavior in college-aged women. Women (N=112) from a public university in the southwest were randomly assigned to intervention or control groups. The 4-week intervention featured an experimental, repeated measures design that used the internet to deliver interactive activities. Control group participants were asked not to change their activity. Walking behavior was assessed by using pedometers to record step counts daily. Data were analyzed using repeated-measures analysis of variance (RM-ANOVA). Women who received the intervention increased their mean steps/day by 38.8% while women who did not receive the intervention increased their mean steps/day by only 2.1% [F(1)=2.61, p=0.001]. A web-based physical activity intervention promoted the short-term adoption of routine walking in college women. (Contains 1 table and 3 figures.)