Epilepsy is usually a chronic disease. It often starts in childhood and sometimes taking anticonvulsant drugs lasts for a whole life. In the last decade the attention was paid on the role of homocysteine in pathogenesis of some neurological diseases. First it was proven that homocysteine high level is a risk factor for ischaemic heart disease, vascular diseases of brain (especially ischaemic stroke), also Parkinson disease, migraine and others. It was also found that patients taking anticonvulsant drugs have higher homocysteine level. It is thought that higher homocysteine level might be connected with taking epileptic drugs, which are the inducers of cytochrome P450. The aim of the study was to measure the plasma homocysteine level at 112 patients with cryptogenic epilepsy. The exclusion criteria were symptomatic epilepsy, diseases of thyroid, renum, liver, vascular diseases of brain. The level of homocysteine in serum was measured by using fluorescence polarization immunoassay method. We also measured the level of vitamin B12 and folic acid. Mean homocysteine level was significantly higher in studied group than in control one, there was not found such a difference as far as folic acid and vitamin B12. Patients on polytherapy had significantly higher level of homocysteine than control group and patients after the first epileptic seizure. The level of folic acid was lower in patients on polytherapy than in controls, there was no such a difference in vitamin B12.