All official Transcripts. A bachelor's degree or its foreign equivalent from an accredited college or university. Official transcripts of your grades. Three letters of recommendation.
Applicants are required to upload a transcript (may be unofficial at this time) including the key from all attended colleges or universities.The transcript must show the name of the student, name of the issuing institution, name of courses taken, and the grades received in those courses.
The Graduate School does not have a minimum TOEFL or IELTS score requirement. If you are offered admission and accept our offer and have scored below a 27 on the Speaking sub-section of the TOEFL iBT or below an 8.0 on the Speaking sub-section of the IELTS you will be required to take an English placement test at the start of the fall term. Students who do not pass the test will be required to enroll in English Language Program classes.
Optional: Applicants may submit a statement with their application, briefly describing how their academic interests, background, or life experiences would advance Princeton's commitment to diversity within the Graduate School and to training individuals in an increasingly diverse society. Please submit a succinct statement of no more than 500 words.
GRE :
General Test optional/not required (recommended), Subject Test optional/not required (recommended)

The M.S. degree is only open to employees of firms with active membership in the department's industrial associates program.