The combination of moyamoya syndrome and symptomatic mesial temporal sclerosis (MTS) has not previously been reported. The authors present the case of a 5-year-old boy with symptomatic MTS who developed progressive moyamoya syndrome. This combination of progressive moyamoya and a structural seizure focus presented a unique clinical problem, with the natural history of MTS predicting a high likelihood of needing resection in the future, which could be challenging following any type of moyamoya-related revascularization surgery. In anticipation of this problem, the patient underwent resection of the right inferior and mesial temporal lobe followed by right pial synangiosis as a 1-day combined operation. Postoperatively he recovered well without any neurological deficits and had an uneventful hospital stay. This case of moyamoya is unique in its association with MTS, and for the simultaneous operations for pial synangiosis and temporal lobectomy, highlighting the importance of surgical planning in patients with dual pathological processes.