Our study was undertaken to identify, to quantify and also to compare the bacterial populations found in six body tissues namely haemolymph, albumen gland, foot, intestine, hepatopancreas and mantle, with that of the habitat soil of slug Laevicaulis alte. Totally six isolates Bacillus subtills, Citrobacter frundii, Serratia marcescens, Enterobacter cloacae, Hafnia and Enterobacter faecalis were isolated from both the habitat soil and from six tissues. Bacillus subtltis is a gram - positive bacteria and the remaining five species are gram - negative bacteria. The study revealed the presence of large number of bacteria found in the hemolymph of Laevicaulis alte. This is due to mollusc-bacteria interactions occuring in natural conditions.