Objetivo : Determinar los factores de riesgo para recurrencia de convulsiones y la clasificacion posquirurgica a corto plazo en pacientes operados por esclerosis mesial temporal (EMT). Metodos : Estudio de casos y controles anidado en la cohorte de pacientes con EMT diagnosticados por resonancia magnetica con dos anos de seguimiento posquirurgico; se excluyeron pacientes con EMT bilateral. Se evaluaron caracteristicas clinicas prequirurgicas, foco epileptogenico en video-EEG y variables quirurgicas con respecto a recurrencia de convulsiones en los primeros dos anos posquirurgicos y clasificacion de Engel en el primer y segundo aniversario de la cirugia. Resultados : Entre octubre de 2001 y junio de 2008 se han evaluado 144 pacientes con EMT candidatos a cirugia de epilepsia; a junio de 2007, se han operado 89 pacientes, 51.7% con EMT izquierda. 35.8% de los pacientes presentaron recurrencia de convulsiones antes del segundo ano posquirurgico; el factor de riesgo prequirurgico asociado a recurrencia fue foco bitemporal o temporal unico con diseminacion contralateral por video-EEG (OR: 6.32; IC95% 1.64-26.41), y posquirurgico, la presencia de convulsiones durante el primer mes posoperatorio (p:0.0004); no se encontro asociacion con recurrencia para: genero, convulsiones tonico-clonicas generalizadas prequirurgicas, lado de la EMT ni tiempo de evolucion prequirurgica de la epilepsia. 66.3% y 75.8% de los pacientes estaban en Engel I al primer y segundo aniversario de la cirugia, respectivamente. 91% de los pacientes intervenidos estaban en buen pronostico posquirurgico a los dos anos. Conclusion : La localizacion del foco epileptogenico por electrofisiologia es factor determinante en el pronostico posquirurgico a corto plazo en EMT. Palabras clave Cirugia de epilepsia, convulsiones, epilepsia del lobulo temporal, esclerosis mesial temporal, factores de riesgo, pronostico, recurrencia. Summary Aim: To establish risk factors for seizure recurrence and short term Engel classification after surgery for Mesial Temporal Sclerosis (MTS). Patients and methods: Nested case-control study in a cohort of patients diagnosed with MTS by magnetic resonance imaging and who had at least two years of postsurgical follow-up; patients with bilateral MTS were excluded. Clinical characteristics, epileptogenic focus in video- EEG and surgical issues were evaluated regarding to seizure recurrence during the first two postsurgical years and Engel classification in the first and second anniversary after surgery. Results : From October 2001 to June 2008, 144 patients with MTS were evaluated as candidates for epilepsy surgery; until June 2007, 89 patients underwent epilepsy surgery, 51.7% with left MTS. 35.8% of patients experienced seizure recurrence before two post-surgical years; presurgical risk factor associated to this recurrence was bitemporal focus or single temporal focus with contralateral dissemination by video-EEG (OR: 6.32; CI95% 1.64-26.41), and post-surgical, seizures that occurred in the first month of surgery (p: 0004). No association with seizure recurrence was found with gender, presurgical tonic-clonic seizures, MTS side and epilepsy duration. 66.3% and 75.8% of patients were Engel I classified in the first and second anniversary after surgery, respectively. 91% of operated patients showed a good outcome after two years of epilepsy surgery. Conclusion : Epileptogenic focus location by electrophysiology is a fundamental factor in short term outcome after surgery for MTS. Key words Epilepsy surgery, mesial temporal sclerosis, outcome, recurrence, risk factors, seizures, temporal lobe epilepsy.