Data from Section 404 permits, which were issued in California from January 1971 through November 1987 and required compensatory mitigation, were compiled and analyzed to determine patterns and trends in permitting activity and to document the cumulative effects of the associated management decisions. Information was gathered on the project permitted, wetland impacted, mitigation project, key contacts, and reports. The 324 permits requiring compensatory mitigation document that 387 compensatory wetlands (1255.9 ha) mitigated for impacts to 368 wetlands (1176.3 ha). The utility of the data on wetland area is limited, however, since approximately 40% of the impacted and compensatory wetlands lacked acreage data. The wetland type most frequently impacted (37.8% of the impacted wetlands) and used in compensation (38.2% of the compensatory wetlands) was palustrine forested wetlands. Estuarine intertidal emergent wetlands had the most area impacted (52.3%) and compensated (62.5%). The majority of the wetlands were small (less than or equal to 4.0 ha in size). Wildlife habitat was the most frequently listed function of the impacted wetlands (90.7% of the permits) and objective of the compensatory wetlands (83.3%). Endangered species were listed as affected in 20.4% of the impacted and 21.0% of the compensatory projects. Less than half (31.5%) of the projects were monitored by at least one site visit. The number of permits issued and the number of impacted and compensatory wetlands increased from 1971 to 1986.