In 1964 at the first Olympic Judo event in Tokyo there were 74 participants from 27 countries. By 1992 in Barcelona the Judo competition had grown to 437 participants from 93 countries. The Olympic weight classes have increased in number over the years. Starting with the Tokyo Olympics, 3 weight categories were introduced in addition to the open category. The categories were expanded to 6 (including an open category) for the 1972 Olympics, and 8 for the 1980 Olympics. In 1992 the open category was dropped from the Olympics, so there are currently 7 weight categories for both men and women in the Olympics.
In 1964 there were 4 men's weight classes as follows: Lightweight (-63 kg/-139 lbs), Middleweight (-80 kg/-176 lbs), Heavyweight (-93 kg/-205 lbs), and Openweight.
In 1968 there was no Judo event, but in 1972 the event was expanded to 6 men's weight classes as follows: Lightweight (-63 kg/-139 lbs), Half-Middleweight (-70 kg/-154 lbs), Middleweight (-80 kg/-176 lbs), Half-Heavyweight (-93 kg/-205 lbs), Heavyweight (Over 93 kg/205 lbs), and Openweight.
In 1980 it was again expanded, this time to 8 weight classes as follows: Extra Lightweight (-60 kg), Half Lightweight (-65 Kg), Lightweight (-71Kg), Half-Middleweight (-78 kg), Middleweight (-86 kg), Half-Heavyweight (-95 kg), Heavyweight (Over 95 kg), and Openweight.
In 1992 the Openweight was dropped and there are 7 remaining official weight classes for men. In addition, women's competition was added to the Olympics as an official medal sport with 7 weight classes (after being a demonstration sport in the1988 Olympics in Seoul, Korea).
The number of weight classes stayed the same, but in 1998 the weights for each category were changed to the following:
| MEN | WOMEN | ||
| Before 1998 | After 1998 | Before 1998 | After 1998 |
| – 60 kg | – 60 kg | – 48 kg | – 48 kg |
| – 65 kg | – 66 kg | – 52 kg | – 52 kg |
| – 71 kg | – 73 kg | – 56 kg | – 57 kg |
| – 78 kg | – 81 kg | – 61 kg | – 63 kg |
| – 86 kg | – 90 kg | – 66 kg | – 70 kg |
| – 95 kg | – 100 kg | – 72 kg | – 78 kg |
| + 95 kg | + 100 kg | + 72 kg | + 78 kg |
See results for Men or Women (by weight class), or see a table of Olympic Medalists by Year.
The motto of the Olympic Games: Citius, Altius, Fortius (faster, higher, stronger)