Bacillus thuringiensis (Bt) is a ubiquitous soil bacterium that produces an array of insecticidal crystal proteins with varied specificities. Recently a lot of effort is being made to collect, characterize, utilize novel and more potent strains of Bt. The crystal proteins (Cry proteins) produced by Bt are important in agricultural, horticultural and public health pest management. In addition to the above recently identified non-insecticidal Cry toxins are being used in cancer research. There is continuing debate among researchers on the species status for Bt and its ecology. The various toxins particularly Cry toxins are important in eco friendly pest management in organic farming and exported oriented crops also. Many cry genes have been engineered into wide variety of crop plants and microbes, offering efficient and effective pest management strategy. Increased efforts to isolate novel strains of Bt from wide variety habitats have yielded valuable strains with new genes. Intensive use of various Bt formulations and high level of expression of various cry genes in Bt transgenic plants have resulted in resistance development in various pest species. But with the judicious use of gene pyramiding and refugia, continued successful pest management is ensured.