Mulaudzi was Junior Champion 1999 Africa in the 800 -meter run. His first medal in the adult area Mulaudzi won at the Africa Championships in Athletics 2000 in Algiers. In 1:46,28 min he took second place behind the Algerian Djabir Saïd - Guernica in 1:45,88 min. 2001 reached Mulaudzi at the World Championships in Edmonton in 1:45,01 min sixth place.
2002 Mulaudzi won in 1:46,32 minutes in the 800 - meter race at the Commonwealth Games in Manchester before the Kenyans Joseph Mutua Mwengi in 1:46,57 min. Two weeks later at the African Championships in Rades, Tunisia, Mulaudzi finished second in 1:46,20 min to third place behind Saïd - Guernica and the Kenyans William Yiampoy.
At the 2003 World Championships in Paris / Saint- Denis Mulaudzi won in 1:44,90 min, another bronze. It won Saïd - Guernica in 1:44,81 minutes before the Russians Yuri Borzakovsky in 1:44,84 min. In October at the African Games in the Nigerian capital Abuja Mulaudzi won silver in 1:46,44 minutes behind Samuel Mwera from Tanzania.
In Budapest at the World Indoor Championships in 2004 Mulaudzi won in 1:45,71 minutes before Rashid Ramzi of Bahrain. At the 2004 Olympic Games in Athens Mulaudzi overtook on the home stretch of the leading Wilson Kipketer from Denmark, both of which were still überspurtet of Borzakovsky. Borzakovsky won gold in 1:44,45 minutes before Mulaudzi in 1:44,61 min and Kipketer in 1:44,65 min.
At the World Championships in Helsinki in 2005 to Mulaudzi surprisingly did not qualify for the final, after he became only third in the slowest intermediate run in 1:45,73 min. At the 2006 World Indoor Championships in Moscow was Mulaudzi in 1:47,16 minutes in goal hundredth of a second behind the Kenyans Wilfred Bungei, the end spurt Borzakovsky could not quite reach the two and was in 1:47,38 min of third parties.
2007 Mulaudzi finished seventh at the World Championships in Osaka. The following year he won the silver medal at the World Indoor Championships in Valencia. At the Olympic Games in Beijing, but he dropped out in the semifinals. At the World Championships 2009 he was in Berlin in a slow race surprising world champion over 800 meters in front of Alfred Kirwa Yego and Yusuf Saad Kamel.
Mulaudzi was 2001-2003 and 2005-2009 South African champion over 800 meters and thus the successor of Ezekiel Sepeng. At a height of 1.71 m his competition weight is 62 kg.
- 800 m - 1:42,86 min ( 2009)
- 1000m - 2:15,86 min ( 2007)
- 1500m - 3:38,55 min ( 2009)