The act expands the list of prohibited immigrants and gives the government greater discretionary authority concerning the admissibility and deportation of immigrants.

Immigrants determined to be “unsuited to the climate or requirements of Canada” are prohibited, as are those sponsored by charitable institutions. Those included are those deemed to be "idiots, imbeciles, feeble-minded, epileptics," and people perceived to be "diseased" and a "challenge to the public health system."