Since 1928, 22 professional agencies have established certification procedures for 52 categories or levels of health laboratory personnel. Surveys indicate that 55% of technical personnel are certified by at least one registry or board. After reviewing some of the pros and cons of certification and its expanding role, the author concludes that certification has become a positive factor in calling attention to the need for quality personnel in health laboratories and has helped meet the needs of individuals and the public. Current movements to work together in a National Commission for Health Certifying Agencies and toward national certification standards are encouraging.