Introduction: Infantile tremor syndrome (ITS) is a nutritional deficiency syndrome, frequently  reported from Indian subcontinent, characterized by skin and hair changes, coarse tremors and developmental delay. The most likely etiology implicated is Vitamin B12 deficiency. West syndrome (WS), on the other hand, is a type of epileptic encephalopathy characterized by a triad of myoclonic jerks, developmental regression and hypsarrhythmias on EEG. The etiology of WS varies from idiopathic to perinatal neurological insult and metabolic causes. Vitamin B12 deficiency has been reported as an etiological factor for WS in various case reports. Case series: We present a series of four children who presented with symptoms consistent with ITS and received standard intramuscular vitamin B12 therapy to which good response was observed. All these children were readmitted with WS with a time lag varying from two months to 12 months. MRI brain and metabolic screen were within normal limits. Two out of four patients responded well to ACTH administration, remaining two required additional drugs. Discussion: Available literature says that vitamin B12 deficiency leads to WS but in our patients, B12 levels were normal in 50% patients. We hypothesized that therapy with Vitamin B12 caused suppression of ACTH and cortisol in CNS leading to presentation of WS. Alternately there might be same underlying mechanism for both conditions. In Indian scenario, it is particularly important to be aware of appearance of WS after ITS, because of high prevalence of ITS and devastating nature of WS.