AIM OF THE STUDY: Factors associated with adherence to self-care and glycaemic control were studied in 213 people with insulin-dependent diabetes mellitus using a self-report questionnaire and a biochemical indicator (glycosylated haemoglobin). METHODS: The data were collected in the Oulu Health Center and the Central Hospital of Lapland in Northern Finland. The response rate was 76%. In order to verify the reliability and validity of the instruments, we used correlation coefficients, factor analysis and item-total analysis. Internal consistency was checked by Cronbach's alpha. The connections between self-care and the background variables were examined by cross-tabulation. FINDINGS: The majority of subjects accomplished their insulin treatment as scheduled, but had more difficulties with the other aspects of self-care. According to the findings, a fifth (19%) of the respondents were neglecting their self-care. The others undertook flexible (46%), regimen-adherent (16%) or self-planned self-care (19%). The subjects who were adherent to self-care had better metabolic control than those who neglected self-care. According to logistic regression analysis, poor metabolic control (P=0.003), smoking (P=0.009) and living alone (P=0.014) were associated with neglect of self-care. Gender, concurrent diseases and complications as a result of diabetes increased the risk, but had no significant association with adherence to or neglect of self-care. CONCLUSION: The findings demonstrated that adherence to self-care does not always lead to good metabolic control, but neglect of self-care is likely to lead to poor metabolic control.