BACKGROUND Round ligament varices (RLVs) are a rare entity that occurs almost only in pregnancy. Given its rarity and perhaps the lack of its awareness, it is not surprising that RLVs are often an overlooked differential diagnosis for inguinal swelling. Furthermore, this is aggravated by the fact that the clinical findings of RLVs on physical examination are usually non-specific and indistinguishable from the other more common causes of groin swelling. CASE REPORT A 35-year-old Asian woman, gravidity 1 parity 0 presented at 26 weeks of gestation with a painless right inguinal lump. She was given a provisional diagnosis of "inguinal hernia." Ultrasonography and color Doppler of the right inguinal lump showed echo-free tubular structures within the right inguinal canal, which became more prominent with Valsalva maneuver and demonstrated vascularity on color Doppler with a venous flow pattern, compatible with RLV. The patient was therefore reassured and treated conservatively. The symptoms spontaneously resolved after a few weeks postpartum. CONCLUSIONS With this case, we hope to increase the awareness of round ligament varices as an important differential diagnosis for an inguinal lump in pregnancy, and highlight the potential difficulty in making the diagnosis clinically. Ultrasonography can serve as a crucial investigation for the prompt and precise diagnosis of RLV, but more importantly, can be a safer alternative to invasive surgical exploration.