Oregon was the first State to decriminalize in 1973, and a Drug Abuse Council survey in 1974 and 1975 found no substantial increase in marijuana consumption. A 1976 survey did reveal a small increase, but this was probably due to changing attitudes toward the drug rather than the law. Data from California also suggest that the prevalence or frequency of marijuana use has not increased since 1974 when the reform law was enacted. A 1978 survey of adults and students in Maine 2 years after its decriminalization law went into effect indicated little increase in use, particularly among adults. Additional surveys by the National Governors' Conference, the National Commission on Marijuana and Drug Abuse, and the National Drug Council tend to support these findings. Oregon, California, and Maine have higher use rates than the national average, but this is not surprising since popular sentiment was sufficient in these areas to change the laws. Public reactions to decriminalization after implementation was mixed in all three States, but the majority approved decriminalization or favored reducing penalties further and felt the law had little impact. California realized substantial cost savings from decriminalization in police departments, courts, State agencies, and corrections, although the mandatory destruction of marijuana possession offense records after 2 years has required some new expenditures. Maine and Ohio have also experienced cost savings from marijuana law reform, but this has not happened in Texas where penalties were reduced considerably but not decriminalized. The paper contains tables and 11 footnotes.