Stage 10 saw the race move into the high mountains, starting with the Pyrenees. On the way to Luchon, four mountain passes had to be crossed: the Col d'Aubisque, the Col du Tourmalet, the Col d'Aspin and finally the Col de Peyresourde, followed by of downhill to the finish line. A total of 30 riders fell on the wet and foggy descent of the Aubisque, including overall contenders Olano, Jalabert and Francesco Casagrande, with the latter being one of six that retired from the race. A three-rider breakaway of Cédric Vasseur (GAN) and Casino-Ag2r teammates Rodolfo Massi and Alberto Elli formed by the foot of the Tourmalet. The pace set by Team Telekom halfway up this climb split the peloton, with yellow jersey wearer Desbiens dropped. Massi moved clear from his fellow riders in the breakaway group on the steep section midway on the -long last climb, and also at the same point after, a move by Ullrich formed a small group of elite riders which included pre-race favourites Pantani, Julich, Riis, Boogerd, Escartín and Jiménez. Close to the top, Pantani launched a successful attack and summitted with an advantage of 42 seconds, but was unable to catch the soloing Massi on the descent, who took the stage victory as well as the lead of the mountains classification. Pantani finished second, 33 seconds behind. Ullrich followed with the other favourites, a further 23 seconds back, to regain the yellow jersey, while Julich moved up to second overall.