A total of 86 resected cases with primary lung cancer were examined on relationships between argyrophil nucleolar organizer regions (Ag-NORs) and other prognostic factors and correlation between Ag-NORs and tumor doubling time (DT). Survival rates were compared between patients with low Ag-NOR counts and patients with high Ag-NOR counts. 1) After logarithmic conversion of mean Ag-NOR counts in lung cancer, a small skewness (0.00486) and a small kurtosis (-0.7859) showed a normal distribution. Mean Ag-NOR counts was found to have a log-normal distribution. 2) There was a significantly inverse correlation between mean Ag-NOR counts and DT (correlation coefficient -0.705, p < 0.001). By plotting log (DT) on X axis and log (Ag-NORs) on Y axis, a formula representing a linear correlation was obtained: Y = 1.17-0.312 X, correlation coefficient -0.886. 3) The five-year survival rate (35%) of 46 patients with mean Ag-NOR counts which were more than or equal to 3.0 significantly lower than that (74%) of 40 patients with mean Ag-NOR counts of less than 3.0.