This study was aimed at evaluating the association between seminal plasma interleukin-8 (sIL-8) and colour-Doppler ultrasound (CDU) characteristics of the male genital tract in a series of patients fulfilling the criteria of male accessory gland infections (MAGI). Of 250 subjects seeking medical care for couple infertility, 79 (mean age: 36.4 ± 7.5 years) met the criteria of MAGI and scored higher than the rest of the sample on the National Institutes of Health-Chronic Prostatitis Symptom Index score. All patients underwent simultaneous hormone evaluation and seminal analysis (including sIL-8), along with scrotal and transrectal CDU before and after ejaculation. After adjusting for age, sIL-8 in patients with MAGI was significantly related to several abnormal semen and CDU parameters. In particular, leucocytospermia was closely associated with sIL-8. Ejaculate volume, unlike other semen or hormonal parameters, was negatively associated with sIL-8. When scrotal CDU was performed, sIL-8 was positively related to CDU inhomogeneous, hypo-echoic, hyper-echoic epididymis and to epididymal calcifications. In addition, a positive correlation among sIL-8, hyperaemic epididymis and an increased size of epididymal tail was found. When transrectal CDU was performed, an association among sIL-8 and hyper-echoic seminal vesicles, dilated ejaculatory ducts and duct calcifications was also observed. Finally, sIL-8 was positively related to prostate CDU abnormalities such as calcifications, inhomogeneous/hypo-echoic texture, hyperaemia and high arterial blood flow. No association was found with testis parameters. In conclusion, sIL-8 levels in patients with MAGI are associated with several parameters and CDU abnormalities of epididymis, seminal vesicles, ejaculatory ducts and prostate, but not of the testis. Furthermore, sIL-8 positively correlates with CDU signs of ejaculatory duct inflammatory subobstruction.