Summary: Purpose: To study the occurrence of partial seizures (PS) and elucidate the characteristics of patients with West syndrome (WS) with PS. Methods: We investigated the electroclinical and radiologic features in 92 children with WS who were older than 3 years at follow‐up. Results: Thirty‐six (39.1%) children had PS at some time during the course of the disease. They had a significantly high incidence of asymmetric spasms, hemiparesis, and asymmetric hypsarrhythmia. Their seizure prognosis was significantly less favorable. PS appeared only before spasms (group A, six children), concomitant with spasms (group B, 18 children), and only after spasms ceased (group C, 12 children). Five children in group B had PS after spasms stopped. PS in group A and during the period of active spasms in group B showed high seizure frequency and variability of both seizures and EEG manifestations. The PS and EEG epileptiform discharges were mainly in parietal‐posterior temporal‐occipital, and central regions. Late PSs in group B and PSs in group C were characterized by stereotyped manifestations and relatively low seizure frequency. These PSs originated mostly from frontal regions. Conclusions: In some children with WS, cortical lesions can induce both PS and spasms in series, whereas in others, both types of seizures occur with abnormally increased excitability throughout the cortex rather than as the result of a single cortical lesion. These findings suggest caution in interpreting focal discharges, which may fluctuate and are not necessarily indicative of a surgically accessible lesion. When the discharges are stable and correlate with an equally stable clinical pattern, the likelihood of an underlying cortical lesion is greater.