This study was performed to compare manual liquid-based preparation with conventional Papanicolaou tests in view of the cytologic diagnoses and specimen adequacy. The specimens of 5,979 women from 33 local clinics and 1 general hospital were prepared by both manual liquid-based preparation and conventional Papanicolaou test. The cytologic diagnoses and specimen adequacy were evaluated in Department of Fathology in Kyoungpook National University School of Medicine. A conventional Papanicolaou test was always prepared first, after that residual material on the sampling device was rinsed into a liquid preservative, and then thin-layer slides were prepared using manual method of liquid-based cervicovaginal cytology. Conventional and liquid-based slides were read independently, and cytologic diagnoses and specimen adequacy were classified using the Bethesda System. Of the cases, 5,763 (96.3%,) had the same interpretation, and there was no significant diagnostic difference in 5,853 (97.8%) cases. When evaluating cases with more than one diagnostic class difference, the manual liquid-based preparation demonstrated a statistically significant overall improvement (2.1%) in the detection of squamous intraepithelial lesion and invasive cancer. Using manual method of liquid-based preparation, there was 14.1%, reduction in unsatisfactory slides through excellent cellular presentation. In conclusion, the manual liquid-based preparation produces standardized quality, superior sensitivity and improved adequacy as compared to the conventional method.