This Fisheries Technical Paper contains some selected papers originally presented at the FAO Technical Consultation on the Measurement of Fishing Capacity held in Mexico City in 1999. The 23 papers are presented in four parts. The first part includes papers addressing theoretical considerations and definitions of capacity. The second part presents case studies outlining the existing practice in some member countries. These case studies do not necessarily represent best practice, but provide an overview of current practice. The third section includes papers that outline alternative methods for deriving output-based measures of capacity. In particular, the papers describe the data envelopment analysis and peak-to-peak techniques. The methods are applied to a number of fisheries for example purposes. The last section contains papers that outline alternative methods for assessing input-based measures of capacity. These include estimation of fishing power, hold capacity and bioeconomic modelling to determine optimal fleet sizes.