Technical Abstract: Synchronization of estrus has several benefits for cow-calf producers including facilitating the use of artificial insemination (AI), improving pregnancy rates to a defined breeding season, improved calving distribution, older calves at weaning, and additional time for postpartum recovery during the subsequent year. Choosing the estrous synchronization program that best fits a producer's needs requires understanding the estrous cycle of cattle and how each protocol and its components work to synchronize estrus. A description of the cow's estrous cycle and a discussion of how synchronization drugs are used to manipulate that estrous cycle are provided. Estrous synchronization protocols discussed in this guideline include the two-injection prostaglandin programs with breeding after each injection or only the second injection, the one-injection prostaglandin program with 10 days of breeding, the melengesterol acetate (MGA)/prostaglandin program, the Select Synch program, the CO-Synch program and use of CIDR intravaginal devices. Regardless of which estrous synchronization program chosen, cattle need to be healthy and on a good plane of nutrition. When using with AI, additional requirements include adequate working facilities with a crowding corral, a holding alley, and a breeding chute, technical experience with semen handling and insemination, accurate detection of estrus, and good record keeping. A cost analysis per pregnancy is included for each protocol so that producers can better decide which protocol best fits their goals.