The biochemical and histopathological changes of L-arginine experimentally induced acute pancreatitis (AP) in male albino rats was investigated. Forty male albino rats were divided into two groups (20 rats each). Group I (control group): rats were fed normal diet. Group II (Acute Pancreatitis Group (AP): Acute pancreatitis was induced in male albino rats by injecting 300 mg/kg bwt of L –Arginine (Arg) intraperitoneally , as a 10% solution in 0.15 M NaCl .Blood samples were collected after 6, 24 and 96 hours and 7 days for acute group schedules. Collected serum samples were directly used for determination of amylase, lipase, alanine aminotransferase (ALT) and aspartate aminotransferase (AST ) activities beside glucose level also tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6 ),nitric oxide (NO),total cholesterol ,triglyceride ,urea and creatinine levels were determined . The obtained results showed significant increases in serum amylase , lipase, ALT and AST activities as well as cholesterol, TNF-α , IL-6 . NO , serum Urea and Creatinine levels. Meanwhile, non-significant change in plasma glucose and serum triglycerides levels were observed. Histopathological changes of L-arginine treated group showed, 24 hours post administration, focal acinar necrosis characterized by pyknosis of nuclei and deeply stained cytoplasm with retention of acinar architecture compared with control group.