Purpose : We aimed to establish the influence of the parameters affecting artificial insemination (AI) results in order to describe the ideal situations to achieve the best results as well as to adequately counsel the patients undergoing these treatments about their pregnancy chances. Methods : We performed a controlled retrospective clinical study over more than one decade in a total of 1858 cycles in 710 patients. Clinical histories and computer registers were systematically reviewed between January 1990 and June 2002. We analyzed the influence of diverse factors affecting AI results such as patient's age, ovarian stimulation, and seminal characteristics to offer a detailed description of the technique. Results : Less than 35-years-old, smooth ovarian stimulation and 5 million of progressive motile sperm inseminated two consecutive days are the optimum conditions for achieving good results. Also, period of time that sperm remained frozen do not affect the result. Furthermore, we present the likely or expected outcomes of these treatments depending on the male and female etiologies. Conclusions : We discourage AI in aged patients, and strongly recommend undergoing ovarian stimulation. Nonetheless, we must reach an adequate amount of sperm with good motility in order to inseminate with maximum guaranties of success.