The Balloon Analogue Risk Task (BART) is a behavioral measure that is commonly used to assess risk taking propensity. The primary goal of the present study was to introduce a mobile version of the BART (mBART) that can be included within ambulatory assessment protocols to assess risk taking in daily life. Study 1 compared common BART indices (i.e., total money earned, adjusted average pumps, balloon explosions, and coefficient of variability [CV]) on a single administration of the laboratory BART on a computer and the mBART on a smartphone (n = 78). Results revealed generally consistent relationships between indices of risk taking propensity in both the laboratory BART and mBART. Study 2 administered the mBART as part of a 7-day ecological momentary assessment (EMA) protocol in a population of nondaily smokers (n = 51). Using multi-level models, results suggest that males have greater adjusted average pumps (p = .03), and that a participant's average CV is negatively related to trait sensation seeking (p = .03) and positively associated with trait positive urgency (p = .04). There were within-person effects of study day (p = .05) and environment (p = .02) with respect to adjusted average pumps such that individuals took greater risks as the study progressed and were riskier when alone compared to with others. Inclusion of the mBART in EMA did not appear to significantly increase participant burden and demonstrated acceptable levels of compliance. These results offer initial evidence supporting the feasibility and utility of the mBART for ambulatory research designs.