Periodontal diseases are heterogeneous group of diseases brought about by the interaction between supragingival and subgingival biofilms and the host inflammatory response. Their treatment comprises of non-surgical and surgical approach provided depending on the severity of the disease. Mostly these non-surgical and surgical approaches result in favourable outcome without any untoward events but in few cases, they might lead to certain complications thatcould alter these predictable outcomes.This book deals on such complications following periodontal flap surgery.