Belus Prajoux Nadjar (born 27 February 1955) is a retired professional tennis player from Chile.

Prajoux won six doubles titles on the ATP Tour during his career. He reached a highest doubles ranking of No. 17 in July 1982. He was a member of the Chile Davis Cup team, and played on the team that reached the final of the 1976 Davis Cup. Prajoux retired from the tour in 1986.

Result	Year	Championship	Surface	Partner	Opponents	Score
Loss	1982	French Open	Clay	Hans Gildemeister	Sherwood Stewart Ferdi Taygan	5–7, 3–6, 1–1 ret.

Result	No.	Date	Tournament	Surface	Partner	Opponents	Score
Win	1.	Jul 1976	Hilversum, Netherlands	Clay	Ricardo Cano	Wojciech Fibak Balázs Taróczy	6–4, 6–3
Loss	1.	Nov 1976	São Paulo,, Brazil	Carpet	Ricardo Cano	Lito Álvarez Víctor Pecci	4–6, 6–3, 3–6
Loss	2.	Nov 1976	Buenos Aires, Argentina	Carpet	Ricardo Cano	Carlos Kirmayr Lito Álvarez	4–6, 5–7
Loss	3.	Dec 1976	Santiago, Chile	Clay	Lito Álvarez	Patricio Cornejo Hans Gildemeister	3–6, 6–7
Win	2.	Nov 1977	Bogotá, Colombia	Clay	Hans Gildemeister	Jorge Andrew Carlos Kirmayr	6–4, 6–2
Win	3.	May 1978	Rome, Italy	Clay	Víctor Pecci	Jan Kodeš Tomáš Šmíd	6–7, 7–6, 6–1
Loss	4.	Jun 1978	Birmingham, UK	Grass	José Luis Clerc	Dick Stockton Erik Van Dillen	6–4, 1–6, 6–3, 6–8, 3–6
Loss	5.	Jul 1978	Stuttgart, West Germany	Clay	Carlos Kirmayr	Jan Kodeš Tomáš Šmíd	3–6, 6–7
Loss	6.	Nov 1978	Buenos Aires, Argentina	Clay	José Luis Clerc	Chris Lewis Van Winitsky	4–6, 6–3, 0–6
Loss	7.	Nov 1980	Quito, Ecuador	Clay	José Luis Clerc	Andrés Gómez Hans Gildemeister	3–6, 6–1, 4–6
Win	4.	Nov 1980	Santiago, Chile	Clay	Ricardo Ycaza	Carlos Kirmayr João Soares	4–6, 7–6, 6–4
Win	5.	Sep 1981	Bordeaux, France	Clay	Andrés Gómez	Jim Gurfein Anders Järryd	7–5, 6–3
Loss	8.	Sep 1981	Palermo, Italy	Clay	Jaime Fillol	José Luis Damiani Diego Pérez	1–6, 4–6
Loss	9.	Nov 1981	Santiago, Chile	Clay	Ricardo Cano	Hans Gildemeister Andrés Gómez	2–6, 6–7
Loss	10.	May 1982	French Open, France	Clay	Hans Gildemeister	Sherwood Stewart Ferdi Taygan	5–7, 3–6. 1–1 ret.
Win	6.	Feb 1983	Viña del Mar, Chile	Clay	Hans Gildemeister	Júlio Góes Ney Keller	6–3, 6–1
Loss	11.	Mar 1983	Nancy, France	Clay	Ricardo Acuña	Jan Gunnarsson Anders Järryd	5–7, 3–6
Loss	12.	Jul 1983	Boston, United States	Clay	Hans Gildemeister	Mark Dickson Cássio Motta	5–7, 3–6

• Belus Prajoux at the Association of Tennis Professionals
• Belus Prajoux at the International Tennis Federation
• Belus Prajoux at the Davis Cup