The overall prevalence of psychiatric disorders in epileptic patients is estimated between 19 and 62%. Depressive disorders may be the most common psychiatric disorders and the main reason for psychiatric hospitalisation and taking psychotropic drugs. The underdiagnosis and undertreatment of depressive disorders among epileptic patients represent a problem of considerable magnitude. The aim of the present study was to evaluate the prevalence of depressive disorders among patients with primary epilepsy and to determine the risk factors of the occurrence of the depressive illness. The survey was conducted in a outpatient epilepsy clinic in the Ibn Rochd University Hospital Centre in Casablanca. All patients with idiopathic or cryptogenic epilepsy aged 15 Years and above, were eligible, except for patients with severe physical and mental disabilities. Neurologists diagnosed the epilepsy based on clinical criteria with electroencephalograms data. The depressive disorders met a psychiatrist's evaluation of an ICD-10 criterion. Ninety-two subjects participated in the survey, 57.6% were men and the mean age was 30.3 +/- 10.8 Years. The epilepsy age of onset was 16.3 +/- 11.4 Years with an average duration of 14.1 +/- 9.2 Years. The prevalence of depressive disorders among epileptic patients in our survey was 18.5%. According to sex, the prevalence was 23.1% in women and 15.1% in men. The depressed patients were compared with the remaining patients without depression with regard to seizure variables and sociodemographic characteristics. The epilepsy-depression and epilepsy-control groups did not differ significantly in the duration of epilepsy or in the type of anticonvulsant therapy (mono versus polytherapy). Three variables were significantly different between the two groups. The mean age in the epilepsy-depression group was significantly higher (34.4 +/- 9.6 Years versus 29.4 +/- 10.9, p<0.03), the mean age of epilepsy age of onset was also higher in the epilepsy-depression group than in the epilepsy-control group (21.8 +/- 11.9 Years versus 15.04 +/- 11.0, p<0.03) and the seizure frequency per week was more important among depressed epileptic patients (2.4 + 5.2 seizures versus 0.4 + 1.5, p<0.007). The present survey confirms the findings of previous studies that the prevalence of the comorbidity between epilepsy and depression is common in specialised outpatient units. The detection and the treatment of depressive disorders among the epileptic patients remains a very great challenge in the management of the epileptic illness. It will improve the quality of life of these patients. A closer involvement of psychiatric and psychological treatment in patient management is necessary.