Haemorrhagic corpus luteum cysts are common causes of acute pelvic pain in women of fertile age. At ultrasound examination, corpus luteum cysts are characterised by spiderweb-like contents but they may also contain bizarre-looking blood clots. This explains why corpus luteum cysts may sometimes be confused with malignancy. Endometriomas may cause pelvic pain but they are also quite common incidental ultrasound findings. A serious condition that may be more or less painful is torsion of the adnexa. Torsion occurs in adnexa containing a lesion, such as ovarian cyst or hydrosalpinx, but it may also occur in normal adnexa, especially in prepubertal girls. Uterine fibroids and adenomyosis may sometimes cause pelvic pain. Gynaecologists should be able to recognise the ultrasound image of non-gynaecological conditions that may cause pelvic pain. Ultrasound images of these conditions may be encountered when an ultrasound examination is performed because of suspicion of gynaecological disease.