Objectives Survivors of pediatric brain tumors and acute lymphoblastic leukemia (ALL) are at increased risk for neurocognitive deficits, but few empirically supported treatment options exist. We examined the feasibility and preliminary efficacy of a home‐based, computerized working memory training program, CogmedRM, with survivors of childhood cancer. Methods Survivors of brain tumors or ALL (n = 20) with identified deficits in attention and/or working memory were randomized to either the success‐adapted computer intervention or a non‐adaptive, active control condition. Specifically, children in the adaptive condition completed exercises that became more challenging with each correct trial, whereas those in the non‐adaptive version trained with exercises that never increased in difficulty. All participants were asked to complete 25 training sessions at home, with weekly, phone‐based coaching support. Brief assessments were completed pre‐intervention and post‐intervention; outcome measures included both performance‐based and parent‐report measures of working memory and attention. Results Eighty‐five percent of survivors were compliant with the intervention, with no adverse events reported. After controlling for baseline intellectual functioning, survivors who completed the intervention program evidenced significant post‐training improvements in their visual working memory and in parent‐rated learning problems compared with those in the active control group. No differences in verbal working memory functioning were evident between groups, however. Conclusions Home‐based, computerized cognitive training demonstrates good feasibility and acceptability in our sample. Children with higher intellectual functioning at baseline appeared to benefit more from the training, although further study is needed to clarify the strength, scope, and particularly the generalizability of potential treatment effects. Copyright © 2012 John Wiley & Sons, Ltd.