The purpose was to analyse the aetiology and ultrasound appearances of segmental testicular infarction. Patients with focal testicular lesions underwent colour Doppler high frequency ultrasound. Segmental testicular infarction was defined as any focal area of altered reflectivity, with or without focal enlargement with absent or diminished colour Doppler flow, proven on histology or on follow-up exclusion of lesion progression. Patients were reviewed to document lesion shape, position, border definition, reflectivity and vascularity and correlated to presenting clinical symptoms and signs. Over a 6-year period 24 patients were defined as having segmental testicular infarction; median age was 37 years (range 16-82 years). All presented with a sudden onset of testicular pain. Of the patients, 14/24 (58.3%) had scrotal inflammatory disease, 5/24 (20.8%) had evidence of spermatic cord torsion, and three patients were termed idiopathic; 12/24 (50.0%) were of low reflectivity, 11/24 (45.8%) of mixed reflectivity, one of high reflectivity, 11/24 (45.8%) were wedge shaped, and 13/24 (54.2%) were round shaped. Of the patients, 8/24 (33.3%) demonstrated a mass effect, all with round-shaped lesions and with underlying epididymo-orchitis in seven. Absent colour Doppler flow was demonstrated in 20/24 (83.3%). Histology confirmed infarction in 8/24 (33.3%), and 12/24 (50.0%) had follow-up examinations without progression of the lesions. Segmental testicular infarction has characteristic ultrasound features, not always wedge-shaped, with reduced or absent vascularity of key importance. Awareness of the ultrasound features will allow for conservative management and avoid unnecessary orchidectomy.