Valentine Prax was born in Bône, Algeria in 1899. She was the daughter of French parents, and attended l'École des Beaux-Arts de Algiers.

In 1919, at the age of 20 she moved to Paris where she enjoyed immediate success. She exhibited at the Salon des Artistes Indépendants that year, then at the Salon des Tuileries. In 1920 she had a solo exhibition at Galerie Mouninou. She continued to exhibit throughout the 1920's at some of the most prodigious galleries in Paris, including Galerie Jacques Bernheim, Galerie Berthe Weill and Galerie Druet. She regularly exhibited at the Paris Salons, she also participated several group exhibitions in Brussels. She painted and exhibited for decades.

Prax was the wife of Ossip Zadkine, one of the most important sculptors of the 20th century; they were married in1920 and were together for over 40 years.

Prax was purely a modernist, and her paintings always have Cubists and Expressionist elements, but her colors are soft and display warmth. Her subjects are lyrical, there seems to be a story to be told in her paintings. She had a long career and produced a large body of work, but she was overshadowed by her husband's success. In recent years there has been more interest in her legacy, including a retrospective exhibition in 1996 at Couvent des Cordeliers in Paris, there was a well-illustrated catalogue produced which shows the range of her contribution.

Prax in represented in many museums including Musée National d'Art Moderne, Musée d'Art Moderne de la Ville de Paris, and the Musée Zadkine near the Boulevard Montparnasse.