In this paper, we report our experiences from the first 30 patients investigated with stereoelectroencephalography (SEEG) at Sahlgrenska University Hospital, Gothenburg, Sweden. Clinical, neurophysiological, and imaging data were reviewed. Twelve children and 18 adults with drug-resistant epilepsy underwent 33 SEEG procedures. 53% of the patients had normal brain MRI. In total, 347 SEEG electrodes were implanted (median 12 per patient). Twenty patients subsequently had resective surgery based on SEEG findings. Focal cortical dysplasia was found in all cases. In 45% of the patients, vicinity of eloquent cortex limited resections. Epilepsy surgery based on SEEG resulted in seizure freedom in 58% of the cases. Minor complications were seen in eight patients, all of which resolved without sequelae. No major complications were seen. SEEG is a safe and effective method to delineate cortical areas involved in seizure generation.