A study was made of the haemolymph protein spectrum of mulberry silkworm (Bomhyx mori L.) from the first larval instar to imago. Horizontal starch gel electrophoresis was used. Sixteen races and eight F1 interracial hybrids, raised in Bulgaria, were analyzed. During the ontogenesis, a total of 17 protein bands (15 cathodic and 2 anodic) were detected. Distinct dynamics in the haemolymph protein spectrum was observed, in result of different expression during the individual development associated with the processes of growth, histolysis and histogenesis. Based on the ontogenetic dynamics found, a correspondence was assumed between some proteins detected by us using the starch gel electrophoresis and major haemolymph proteins (SP1, SP2, MHPs and Vg) detected by other authors using the polyacrilamide gel electrophoresis. Intraracial and interracial polymorphism was observed in four protein zones. The effect of four polymorphic loci with codominant and null alleles was suggested.