Psychopathological factors associated with metabolic control in juvenile insulin-dependent diabetes mellitus (IDDM) deserve further investigation. This study assessed the relationship among specific psychopathological dimensions, coping mechanisms, and metabolic control in a Croatian clinical sample of adolescents with IDDM. One-hundred and one adolescents (aged 11-18) with IDDM filled out the youth self report (YSR) assessing psychopathological dimension and the scale of coping with stress (SCS). Glycemic control was estimated by the percentage of glycated hemoglobin (HbA1c). Subjects were divided into three groups according to HbA1C values: "optimal", "suboptimal control", and "at high risk". Subjects in optimal glycemic control presented with significantly lower scores in most of YSR scales compared to subjects at high risk. Moreover, they had significantly lower scores in avoidance and emotional reactivity and significantly higher scores in cognitive restructuring and problem solving SCS subscales. Regression models revealed that both internalizing and externalizing YSR scores, as well as emotional reactivity coping scores, independently contributed to explain variability of HbA1C values. Both internalizing and externalizing psychopathological dimensions, as well as emotion-oriented coping strategies, are independently associated with poor metabolic control in both boys and girls with IDDM, thus representing potential interest targets of psychotherapeutic interventions aimed at improving glycemic control in this population.