The major activities of NIOSH during 1978 are reviewed. Areas of health surveillance; health, safety and control technology research; recommended standards, guidelines and hazard notifications; technical assistance and training and human resource development are discussed. NIOSH issued 18 criteria documents, 10 Current Intelligence Bulletins, performed 6 Special Hazard Reviews, and validated 29 methods as part of the joint NIOSH/OSHA Standards Completion Program. Ninety nine Health Hazard Evaluation Toxicity Determination Reports were completed and 41 Technical Assistance Requests were answered. NIOSH issued 35 respirator certifications and 208 extensions of respirator certifications. Forty seven sampling and analytical methods were developed, 40,459 analyses were performed on 16,978 samples and 80 training courses for 3,300 occupational safety and health practitioners were conducted. A total of 1.5 million copies of publications were distributed. The health and hazard surveillance program completed four reports including a study of chemical workers in Massachusetts, and angiosarcoma of the liver in vinyl chloride/polyvinyl chloride workers, and a rural health study. Acquisition of computerized data on 4 million establishments was completed. Occupationally induced malignancies in specified industries also were studied.