OBJECTIVE This prospective study was designed to determine whether ultrasound (US)-guided percutaneous fine needle aspiration biopsy (PFNAB)/US-guided percutaneous needle core biopsy (PNCB) of abdominal lesions is efficacious in diagnosis, is helpful in treatment choice, to evaluate whether various other investigations can be avoided, especially invasive ones, its time (shortening hospitalization) and cost-effectiveness. METHODS A total 159 US-guided PFNAB (67) and US-guided automated PNCB (92) of abdominal lesions were performed percutaneously in 150 patients; the youngest patient was a 3-month-old female and eldest was a 75-year-old female. The patient selection was irrespective of age, sex, or location of the abdominal lesion. These patients presented with abdominal mass/lesions, suspected malignancy, jaundice, and in some cases, however, biopsy was performed to determine the nature of indeterminate lesion (malignant / benign versus abscesses). They were 47 hepatobiliary, 6 pancreas, 24 gastrointestinal tract (GIT), 20 kidneys and urinary bladder, 20 prostate, 3 lymph nodes, 4 adrenals, 8 retroperitoneal, 13 ovaries, and 9 other types of lesions. We used free-hand technique (without biopsy attachment) in 129 cases, and transrectal and transvaginal with biopsy attachment was used in 30 cases. RESULTS In 91.99% of cases, US-guided PFNAB/US-guided PNCB contributed significantly to diagnosis in which US-guided PFNAB/US-guided PNCB was the diagnostic test in 23.33% cases. It confirmed a highly suspected diagnosis in 64% patients, and indicated a specific diagnosis that was not suspected in the remaining 36%. In 57.33% cases, the results of US-guided PFNAB/US-guided PNCB, did not alter treatment choice but increased physician confidence in the choice. US-guided PFNAB/US-guided PNCB was responsible in avoiding 107 planned investigations, including 8 laparotomies, with no significant complications and decreasing length of stay and resulting in 20% cost savings. CONCLUSIONS Thus, the US-guided PFNAB/US-guided PNCB contributed significantly in diagnosis, and in most of the cases it did not change treatment choice but increased clinicians confidence in the choice. We can avoid the number of investigations, decrease morbidity and mortality, shorten hospitalization and cost by using these methods.