The present investigation entitled, "Population dynamics and management of cabbage white butterfly, Pieris brassicae (Linn.) in district Sultanpur (U.P)" was carried out at the Farmer field, village Bhain, district Sultanpur, U.P. during the rabi season 2012-13 and 2013-14. In order to see the incidence and management of invasive pest i.e. cabbage white butterfly, which is a regular pest and causing heavy damage in the Himachal Pradesh, some parts of Uttarakhand and U.P., . Incidence of this pest is studied to plan the dates of sowing, in order to escape the pest infestation. Management is done with the chemicals and bio pesticides to minimize the indiscriminate use of insecticides for the pest i.e. cabbage white butterfly (Pieris brassicae). Laboratory study was also carried apart from the field work on biology of cabbage white butterfly and mortality of catterpillars against certain chemical and bio-pesticides. Studies on the incidence of cabbage white butterfly (Pieris brassicae) population with weather parameters given in table 4.1, figure 4.1 and table 4.2, figure 4.2. The occurrence of cabbage white butterfly (Pieris brassicae) was commenced from 4th standard week.