This meta-analysis aimed to systematically collect and synthesize the current evidence regarding the efficacy and tolerability of levetiracetam (LEV) as an adjunctive therapy for adults and children suffering from idiopathic and secondary epilepsy of multiple seizure types. We selected randomized-controlled trials (RCT) of LEV as an adjunctive therapy in epilepsy according to predefined criteria. Outcome measures included a>> or =50% reduction in seizure frequency, seizure freedom, and adverse events. Thirteen RCT were analyzed. Results showed that the efficacy of adjunctive LEV was superior to placebo both in achieving>> or =50% reduction in seizure frequency (pooled odds ratio [OR] 3.36, 95% confidence interval [CI] 2.78-4.07, Z=12.46; p<0.00001) and seizure freedom (pooled OR 4.72, 95% CI 2.96-7.54, Z=6.50; p<0.00001). The heterogeneity was mild (chi-squared=12.28, I2=2% in>> or =50% reduction in seizure frequency, and chi-squared=0.49, I2=0% in seizure freedom). Subgroup analysis suggested similar effects across different dosages in adults. The incidence of adverse reactions was not significantly different between the LEV group and the placebo group. The adverse events of relatively high incidence in the LEV group included somnolence, agitation, dizziness, asthenia, and infection. Incidence of serious adverse reaction such as rash and white blood cells and platelets decreasing was quite low. Adjunctive therapy with LEV was superior to placebo in reducing the frequency of seizures in patients with partial and idiopathic generalized epilepsy with effect in both adults and children, and demonstrated good tolerance in patients with epilepsy.