Few published reports have documented the value of SMBG on glycemic control in patients with non-insulin-dependent diabetes mellitus (NIDDM), and no reports have evaluated predominantly African American patients who are at high risk for NIDDM and associated complications. In this study a 13-item survey was given to 98 patients with NIDDM to assess the frequency of self-monitoring of blood glucose (SMBG) and its impact on glycemic control. Sixty-one patients performed SMBG and 37 did not. More SMBG testers were taking insulin compared with the nontesters. GHb was comparable between groups. Among the testers there was no difference in mean GHb values based on the frequency of SMBG. Most testers performed SMBG before meals (93%) and recorded their values (85%); many had difficulty obtaining a good blood sample (30%). The most common reason for not testing was cost of supplies (77%). Performance of SMBG in these NIDDM patients was not associated with better glycemic control. Cost was a prohibitive factor for the nontesters.