Use of information technology in diabetes management has been shown to improve self-care. We determined whether enhancing type 2 diabetes (T2DM) self-care with a personal digital assistant (PDA) by patients in the ambulatory setting would improve glycemic control. A pretest/posttest intervention study was conducted in four family practice clinics in a large multispecialty group practice associated with an 186,000-member Health Maintenance Organization. Adults with T2DM and last measured glycosylated hemoglobin (HbA1c) of > or = 8.00% received one-on-one training on the use of a loaned PDA pre-installed with "Diabetes Pilot." Changes in HbA1c and other outcomes were assessed at 6 months from baseline for all participants and by participant-reported PDA use patterns, dichotomized into high PDA users (> or =3 days in past 7) and low PDA users (< 3 days). Of 43 subjects enrolled, 18 (41.90%) completed the 6-month intervention. Their mean HbA1c decreased 17.50% from 9.70% at baseline to 8.00%, a significant mean HbA1c change of -1.7% (95% CI = -2.60 to -0.90). The mean HbA1c change was higher among reported high PDA users (n = 9, mean difference = -1.90, 95% CI = -3.20 to -0.50) than among reported low PDA users (n = 9, mean difference = -1.50, 95% CI = -2.80 to -0.30). Significant increases were reported for the foot care and general diet subscales of the Summary of Diabetes Self-Care Activities from 3 to 6 months. Enhancing T2DM self-care by adults with a PDA was associated with significant reductions in HbA1c; the reductions were greater among reported high PDA users.