This thesis was undertaken to assess the population health and demographics of free-roaming dogs in the city of Jodhpur, India and to quantify the impact of an Animal Birth Control (ABC)/rabies vaccination program (introduced in 2004) on these parameters. Between 2005 and 2007, dog population size declined significantly (p<0.05) in 4 of 6 areas in Jodhpur. By 2007, 61.8% to 86.4% of the adult and subadult stray dog population had been spayed/neutered through the ABC program. Among sexually intact dogs, 69.7% (95% CI=64.3-74.6%; n=323) were underweight, 68.9% (95% CI=63.5-73.9%) had skin conditions, 68% (95% CI=62.6-73.0%) had ticks, and 9.0% (95% CI=6.2-12.8%) had open wounds. The seroprevalence of Brucella canis was 1.1% (95% CI=0-3.1%; n=456) using an indirect ELISA. The prevalence of transmissible venereal tumor was 3.1% (95% CI=1.6-5.8%; n=323) and of pyometra was 1.2% (95% CI=0.3-3.8%; n=246). Fetal resorption occurred in 32.6% of pregnancies (95% CI=20.5-48.7%; n=43). Our data supported the hypothesis that pregnancy was seasonal (p<0.001), but not that estrus was seasonal (p=0.823). The odds of being lame were 1.5 times greater (95% CI=1.1-2.3) for male dogs than for females. The prevalence of lameness in male dogs was 17.3% (95% CI=13.8-20.7%; n=458) and in females was 12.0% (95% CI=8.8-15.1%; n=412). Spayed/neutered dogs had significantly (p<0.001) greater odds (OR=1.7; 95% CI=1.3-2.2) of having a skin condition than sexually intact dogs, possibly due to exposure to contact-transmitted skin conditions during transport to and during their stay at the spay/neuter facility. The odds of having an ideal Body Condition Score (BCS) versus an emaciated BCS were 1.6 (95% CI=1.1-2.3) times greater for spayed/neutered dogs compared to sexually intact dogs (p=0.028) when controlling for the effects of age and gender. This is the first study to quantify the health impacts of an ABC program on a population of stray dogs, and it provides baseline data on stray dog health for monitoring the long-term impacts of ABC in Jodhpur.