Background: This paper will evaluate the use of adrenocorticotropic hormone as a therapy modality for West syndrome and the time required for development of the severely progressive form of West syndrome (LGS, Lennox-Gastaut syndrome). There is little data on this condition for our population. Material and Methods: This is a cohort review in which 139 patient records were evaluated in two pediatric units in Lima, Peru; and they were analyzed between 2000 and 2010. All patients who met the following criteria were included in the study: massive spasms, delayed psychomotor development, and hypsarrhythmia in electroencephalogram (EEG) tracing. Adrenocorticotropic hormone was administered to a group of patients as post-diagnosis therapy. The follow-up period for these patients was 10 years. Results: The hazard ratio (HR) for progression to Lennox-Gastaut Syndrome in patients using adrenocorti...