Objective: To determine the early clinical improvement in low albumin patients with Clostridium difficile associated diarrhea (CDAD) after treatment with oral vancomycin compared to oral metronidazole.Patients and Methods: Tewenty-six low albumin CDAD patients were randomized to received oral vancomycin or oral metronidazole for at least 5 days.  Clinical data were recorded at the day of diagnosis and at day 5 after to compare early clinical improvement (at day 5) between both groups.Results: All low albumin CDAD patients, ten were randomized to receive oral vancomycin and sixteen to receive oral metronidazole.  There was no significant difference in clinical data at the day of diagnosis (day 0) and day 5 after treatment between both groups except the decreasing of bowel movement.  Bowel movement < 2 times per day was found in vancomycin group more common than in metronidazole group.  All clinical signs and symptoms (body temperature <38 °C, absence of abdominal pain, bowel movement ≤2 times per day) of early clinical improvement were shown at day 5 in vancomycin groups.  However, there was no statistical difference between both groups.  One patient from metronidazole group died from pneumonia with sepsis before finished 5 days of treatment.Conclusion: Oral vancomycin treatment seems to have a better effect for low albumin CDAD than oral metronidazole treatment but it was not significant by statistic analysis.