This paper aims to evaluate the reliability and validity of the Integral Quality of Life Scale in people with intellectual and developmental disability in the Chilean people. That is a principal instrument to evaluate the quality of life in this collective from subjective and objective vision. For this, 751 students have participated and 82 professionals. The main results show that there is adequate instrument reliability and factorial Chilean population structure is fully consistent with the Spanish version. The results confirm that the Integral Scale is a valid and optimum reliability instrument in Chilean population to assess the quality of life for people with intellectual and developmental disabilities.