The title of this research is the Supervision of the Toba Regency Environmental Service of PT Toba Pulp Lestari (PT TPL) as an Effort to Prevent Environmental Pollution in Parmakasian District, Toba Regency. Pollution in the Parmaksian District of Toba Regency is one of the problems in this study. Toba Regency is an industrial area, and industries that produce waste waste that can cause pollution, environmental pollution is very dangerous and very disruptive to life, therefore it is necessary to supervise to avoid pollution. The purpose of this research is to find out how the implementation of supervision from the Toba Regency Environmental Service on PT Toba Pulp Lestari (PT TPL) as an effort to prevent environmental pollution. Writing using empirical legal writing methods that emphasize the study of applicable law and what happens in the reality of society. The conclusion of this research is that the implementation of supervision carried out by the Toba Regency Environmental Service against PT Toba Pulp Lestari has been carried out quite well. The Environmental Service has conducted supervision to prevent environmental pollution.