This study was conducted to investigate some pharmacological effects of ciprofloxacin and levofloxacin in their therapeutic and double therapeutic doses on healthy male albino rats. Forty five rats were divided into 5 groups, each of 9 rats, 1 st was left as a control, 2 nd and 3 rd groups received 100 mg/kg BW ciprofloxacin and levofloxacin respectively, orally for 10 successive days (therapeutic dose). The 4 th and 5 th groups were administrated 200 mg/kg ciprofloxacin and levofloxacin respectively, orally for 10 successive days (double therapeutic doses). Urine analysis and serum biochemical parameters were estimated in addition to histopathological examination of liver and kidneys. The urine analysis revealed that levofloxacin at its therapeutic and double therapeutic doses produced a significant increase in urinary proteins, blood, bilirubin, urobilinogen and urinary ketones while ciprofloxacin doses produced less damage. However, serum biochemical parameters disclosed that levofloxacin is a safer fluoroquinolone than ciprofloxacin; these results were confirmed by histopathological examination of liver and kidneys. Urine analysis despite widely used in human laboratories, it is not a reliable technique; blood biochemical parameters examination and histopathological examination are more dependable.