The Convention on the Rights of Persons with Disabilities stresses that persons with disabilities should be able to participate fully in all aspects of life, including education. Nevertheless, statistics shows than a low percentage of persons with disabilities complete higher education. MOOCs, being online courses available to a very large number of people, have a great potential to satisfy the learning needs of millions of people. When designing a MOOC, it is important to consider the diversity of abilities of all potential learners. Genuine universality and openness can only be achieved if all kind of users can access and use MOOCs to engage in learning regardless their abilities. This paper proposes two categories of web accessibility requirements: for personal and for non-personal disabilities. Each category is characterized and a preliminary list of web accessibility requirements for each one is presented. Both MOOC's platforms and contents must meet web accessibility requirements. If contents are accessible but not the platform, or vice versa, the MOOC is not accessible.This work is partially funded by the Prometheus project of the National Secretary of Higher Education, Science and Technology (SENESCYT), Government of Ecuador