With more public awareness about environmental issues mainly in developed countries when they found the Chlorophenolic compounds (AOX) in the fish stock receiving bleach plant effluent, draw much attention regarding the toxicity value of bleach plant effluent. In this paper, I have mainly described the fish toxicity and microtox toxicity value of bleach plant effluents and their relationship in agro & wood based mills. Toxicity studies were done on chlorination stage, Extraction stage, Hypo stage and combined bleach effluents of agro and wood based mills. Studies show that the E-stage effluents are having high fish mortality rate at lower % volume concentration & high % inhibition of Luminescent bacteria, indicating that it is more toxic than the other stage bleach effluent. Studies also shows that scenario of agro based small pulp and paper mills are not good and releases high toxic bleach effluent as compared to wood based large pulp and paper mills due to low scale of operation and use of high dose of bleach chemical due to economical reason.