Objective To assess the frequency and predictors of regular monitoring of metabolic parameters as recommended by the American Diabetes Association (ADA)/American Psychiatric Association (APA) guidelines in adolescents receiving antipsychotics compared with an untreated comparison group in a primary care setting. Method A retrospective cohort study was conducted using an electronic medical record database in the USA from January 2004 to July 2009. The exposure group consisted of adolescents with a first prescription for second-generation antipsychotics (SGAs). The comparison group, without antipsychotics, was matched (3:1) to the exposed. Baseline and follow-up metabolic measurements were assessed and patients were categorised as being regularly monitored based on recommendations by the ADA/APA guidelines. Multivariate logistic regression was conducted to assess the predictors of regular monitoring, adjusting for demographic characteristics, baseline medications and medical conditions. Results The frequency of regular monitoring of body mass index (BMI), blood pressure, total cholesterol and fasting blood glucose, as recommended by ADA/APA guidelines among antipsychotic users (25, 55, 2.4 and 1.7%) was low but significantly higher compared with the matched comparison group (9.5, 37.4, 0.8 and 0.7%, respectively) (P0.05). Overall, antipsychotic treatment was associated with 1.5- to 4.26-fold increase in the likelihood of metabolic monitoring compared with the comparison group (P0.05). Other predictors included oral antidiabetic use for BMI monitoring and dyslipidaemia for blood pressure, total cholesterol and fasting blood glucose. Conclusion The majority of adolescents on antipsychotics were under-monitored for BMI, lipids and glucose levels. Antipsychotic users with pre-existing and newly diagnosed metabolic conditions were more likely to be regularly monitored for metabolic parameters.