She started her business life in the marketing department of Procter & Gamble Turkey in 1991. She joined DanoneSA Tikveşli company of DanoneSA, a Turkish joint venture company of Groupe Danone with Sabancı Holding, and became marketing director and member of the executive committee in 1999. She was appointed general manager and chairperson of the executive committee at DanoneSA Diary Products in June 2002.

In following years, Serpil Timuray was engaged in the takeover of DanoneSA companies and Nestlé Turkey Diary Products by the Danone Group with their subsequent consolidation and integration. She was jointly responsible for Danone Group's one of the most comprehensive industrial investment programs worldwide. She administered so a 100%-domestic production realized in Turkey.

On November 11, 2008 she transferred to Vodafone Turkey. Timuray became its chief operating officer on January 1, 2009. She helped the company grew more than 30%.