²¹⁰Po was determined in 24-h urine of seven healthy males from Prague, Czech Republic, for ten consecutive days. The results show that for each volunteer, the urinary excretion of ²¹⁰Po changed only little from day to day in the studied time period. For two volunteers, the difference in the daily excreted ²¹⁰Po activity for two consecutive days was not significant, given the 95 % confidence interval (two sigma) of the activity measurements. The same is valid for the excretion data of the other volunteers, except for some days where the differences were slightly higher. The range of daily urinary excretion of ²¹⁰Po of each volunteer in the studied time period was quite narrow. Among the volunteers, the maximum daily urinary excretion value of ²¹⁰Po was at most about a factor of 2.5 higher than the lowest excretion value. An attempt to explain the observed small inter-individual variability of ²¹⁰Po excretion in daily urine is made.