Identification of the significant factors that affect codling moth pheromone trap catches is necessary for the establishment of standardized trapping procedures and optimal mass-trapping programs. Trap catches were higher when traps were placed toward the tops of apple trees and outside the canopy. Traps that were aligned parallel to the prevailing evening air movement caught more moths than traps aligned perpendicularly. As trap/tree density increased in a given area, the number of moths caught per trap decreased, but at a rate that was less than would be expected if the total catch of all the traps were the same for all densities. The total number of moths caught per plot increased as the trap/tree density increased. The two highest densities tested (1 trap/tree and 1 trap/2 trees) caught the most moths. These densities did not reduce the mating success of tethered females below that of females in an untrapped plot which suggests that mass-trapping in an orchard with a high population density of moths is not feasible as part of a pest management program.