The identification and selection of new superior bivoltine silkworm hybrids involve six silkworm purelines (DMMMSU 108, 109, 110, 111, 113 and 119). A diallele mating plan was made resulting to 30 silkworm hybrids. The Combining ability effects of the six purelines of mulberry silkworm Bombyx mori and their 30 F1 hybrids were evaluated and analyzed. Data on effective rearing rate, cocoon yield, single cocoon weight and cocoon shell percentage were considered in selecting the best parents and hybrids. Significant variations among genotypes were established hence combining ability analyses were done. Among the six parents, DMMMSU 119, 111 and 110 are the best combiners to improve cocoon yield, DMMMSU 110 and 119 for single cocoon weight, DMMMSU 111 and 110 for effective rearing rate. DMMMSU 119 and 108 for cocoon shell percentage. These purelines, in particular, could either be used as a male or a female parent in developing F1 hybrids. Based on the combining ability test and evaluation index, DMMMSU 119x108, DMMMSU 110x119, DMMMSU 110x113, DMMMSU 119x111 and DMMMSU 108x119 are the selected superior hybrids. These hybrids showed positive combining ability effects and a high evaluation index in all the characters studied. Their superiority is due to the possible dominant action of genes contributed by the parent with positive combining ability effects. These silkworm hybrids are potential for commercial cocoon production, thus, provide an opportunity to fill in the country’s growing demand for silk.