HFSP postdoctoral fellowships encourage early career scientists to broaden their research skills by moving into new areas of study while working in a foreign country. Fellows may choose to stay for up to three years in the host country or use the last year of their fellowship to return to their home country or to move to another HFSPO member country. The program offers Long-Term Fellowships (LTF) for applicants with a Ph.D. in a biological discipline and Cross-Disciplinary Fellowships (CDF) for applicants with a Ph.D. from outside the life sciences (e.g. in physics, chemistry, mathematics, engineering or computer sciences), who have had limited exposure to biology during their previous training.