O'Brien Foundation fellowships are awarded through an annual competition. In its forty-two years of operation, from 1975 to 2025, the Foundation received 2,746 applications and granted 405 fellowships. The total value of the awards granted in these years was 2,427,000.00.
The fields of study of the recipients are shown in the accompanying tabulation.
| Field of Endeavour | Number | Amount |
| History | 29 | $153,500 |
| Biology | 31 | 180,500 |
| Psychology | 37 | 219,800 |
| Music | 23 | 97,500 |
| Education | 24 | 99,500 |
| English | 14 | 77,500 |
| Medicine | 12 | 66,000 |
| Zoology | 15 | 64,000 |
| Law | 13 | 57,000 |
| Political Science | 10 | 51,500 |
| Geology | 9 | 56,500 |
| Chemistry | 13 | 59,000 |
| Mathematics | 6 | 35,000 |
| Physics | 10 | 41,500 |
| Anthropology | 5 | 31,500 |
| Health Science | 9 | 43,000 |
| Philosophy | 4 | 19,500 |
| Engineering | 7 | 45,200 |
| Agriculture | 5 | 18,000 |
| Dentistry | 5 | 15,500 |
| Sociology | 5 | 22,500 |
| Museum Studies | 4 | 12,500 |
| Geography | 2 | 12,000 |
| Business | 2 | 11,500 |
| Anatomy | 2 | 9,000 |
| Veterinary Medicine | 2 | 9,000 |
| Pharmacology | 2 | 8,500 |
| Fine Arts - Sculpture | 2 | 15,500 |
| Environmental Studies | 5 | 19,000 |
| Theatre | 3 | 7,500 |
| Ecology | 3 | 16,500 |
| Archeology | 1 | 6,000 |
| Economics | 1 | 6,000 |
| Linguistics | 2 | 15,000 |
| Forestry | 1 | 5,000 |
| Physical Education | 2 | 5,000 |
| Theology | 1 | 5,000 |
| Astronomy | 1 | 5,000 |
| Law Enforcement | 1 | 2,500 |
| Computer Science | 1 | 10,000 |
| Interdisciplinary Studies | 1 | 6,000 |
| Alumni Fellowship Awards | ||
| Music | 2 | 20,000 |
| History | 2 | 10,000 |
| Neuroscience | 1 | 5,000 |
| Health Science | 1 | 5,000 |
| Medical Physics | 1 | 10,000 |
| Total | 333 | $1,707,000 |