Aim: To classify (etiologically) and to evaluate various scrotal pathologies using ultrasonography and describe the role of High resolution ultrasound and colour doppler in their diagnosis and differentiation. Methods: A prospective study was conducted in the Department of Radiodiagnosis, Indira Gandhi Institute of Medical science, Patna, Bihar, India, for 15 months. The 100 patients with clinical features of scrotal diseases were include in this study. All the patients included in the study underwent scrotal ultrasonography using 7.0- 12.0 MHZ high frequency linear array transducer coupled with Colour Doppler in Esaote My Lab 40 and Phillips affinti 70G equipments. Results: The patients most commonly involved were those belonging to the age group of 30 to 40 years (38%). The least number of patients belonged to the age group of 0-10 years (4%). On USG, the total number of lesions detected were 120. The most common cause of scrotal pathologies was hydrocele (n=31, 25.83%) followed by epididymal cyst (n= 20, 16.67%), epididymo-orchitis (n =16, 13.33%), epididymitis (n = 9; 7.5%), funiculitis (n=8, 6.67%), varicocele (n = 7, 5.83%), pyocele (n= 6, 5%), testicular torsion (n=5, 4.17%), testicular abscess (n = 5, 4.17%), inguino-scrotal hernia (n = 4, 3.33%), testicular microlithiasis (n= 3, 2.5%), testicular tumour (n=3, 2.5%) and tubercular epididymo-orchitis (n=3, 2.5%) . The number of scrotal lesions seen on the left side were 45(37.5%), on the right side were 35 (29.17%) and in bilateral locations were 20(16.67%). Associated symptoms included swelling, pain, fever and infertility. Almost all the scrotal pathologies were associated with scrotal swelling (n=97, 97%) except in 3 cases. Epididymal cysts were seen in 20 patients, Acute epididymo-orchitis(n=16) was most commonly seen on the left side. Hydrocele (n=31) was the most common scrotal pathology detected in this study. Varicocele 7 patients was most commonly seen on the left side. Testicular torsion was detected in 5 (n = 5) patients. 3 (n=3, 60%) patients had right testicular torsion. Conclusion: High frequency ultrasonography with Color Doppler study serves as an excellent diagnostic imaging modality in the evaluation of scrotal diseases. It is the investigation of choice since it is highly sensitive, easy to perform, widely available, repeatable and involves no risk of ionizing radiation. Periodic follow-up USG scans are recommended for patients with inflammatory scrotal lesions to monitor response to treatment and to reveal the development of complications.