Until recently, adenomyosis has been associated with multiparity, not impaired fertility. Currently, adenomyosis is diagnosed with increasing frequency in infertile patients since women delay their first pregnancy until their late 30s or early 40s. Although an association between adenomyosis and infertility has not been fully established, based on the available information, recent studies suggested that adenomyosis has a negative impact on female fertility. Several uncontrolled studies with limited data also suggested that treatment of adenomyosis may improve fertility. This article discusses (i) the hypothesis and epidemiology of adenomyosis, (ii) diagnostic techniques, (iii) clinical evidence of correlation between adenomyosis and infertility, (iv) proposed mechanism of infertility in women with adenomyosis, (v) different treatment strategies and reproductive outcomes, and (vi) assisted reproductive technology outcome in women with adenomyosis.