The present disclosure provides methods and kits for performing high multiplex PCR using molecular barcodes. The methods disclosed herein separately extend a set of primers (BC primers) that each comprise a target-specific sequence, a molecular barcode and a universal sequence, and amplify the resulting extension products using another set of primers (LA primers) that each comprise another target-specific sequence and a universal sequence. The methods may further comprise amplification using universal primers (preferably comprising an adapter).