<b><i>Background:</i></b> In this paper we describe a novel Internet-based cell phone-optimized assessment technique (ICAT) to conduct an ecological momentary assessment (EMA) study. Participants could access the assessment instrument via the web browsers of their mobile phones. <b><i>Methods:</i></b> We report results from 92 young adult smokers (18-25 years old) who completed the baseline assessment and the first of 4 waves (3 days/wave) of EMA. Random prompts were issued via text messages sent to the participants. The participants were also instructed to self-initiate reports of smoking situations. <b><i>Results:</i></b> Compliance with the study protocols was low. In total, the participants completed 885 assessments during the 3 days of monitoring. Only 50.2% of random prompts were responded to, and 52.4% of those were completed within the first 10 min after issuing. Furthermore, reports of smoking situations were rarely self-initiated. In a multivariate regression analysis, age (positively) and female gender (negatively) predicted the number of completed assessments. <b><i>Conclusions:</i></b> This study adds to the limited experiences made with ICAT in substance use research. Similar to the few prior ICAT studies, compliance was low compared to traditional EMA studies. While using ICAT is technically feasible, specific improvements should be implemented to tap ICAT's full potential in future studies.