Secondary teachers participating in summer professional development chemistry workshops in Texas used an online chemistry tutoring program, OWL Quick Prep (Day et al. in OWL: Online Web-based Learning, Brooks-Cole Cengage Learning, Florence, KY, 1997) as a part of the inservice training. Self-reported demographic data were used to identify factors in preparation and practice that affected pretest and posttest scores. Data from the pretests and posttests indicate that nomenclature and problems requiring calculations were the most challenging topics for the cohort. The participants who correctly completed 90% of the questions in the tutoring modules showed significant improvement in content mastery.