This is a part of research work undertaken in the Department of Zoology, S. V. University, Tirupati, to ascertain the neurotoxic potentiality of synthetic pyrethroid, Fenvalerate in Central Nervous System (CNS) of Cockroach, P. americana. The study gives an insight on how insecticides affect target insects under different modes of application. The manifestation of behavioural changes following Fenvalerate intoxication have been documented. Perturbations in some selected aspects of protein and carbohydrate metabolic profiles have also been studied in CNS under acute and sub-acute doses of Fenvalerate. To draw a possible correlation between metabolic and physiological aspects of nervous system, alterations in electrical activity such as amplitude, threshold, latency and duration of evoked potentials in CNS have also been recorded and discussed. The results highlighted the biodegradability of pyrethroids in general and Fenvalerate in particular atleast under sub-acute doses. If applied with care and discretion, it can be used in agricultural pest control practices without deleterious effects on non-target organisms.