The invention relates to treatment of cancers and cancerous cells which over-express .alpha. folate receptor (FR.alpha.) compared to the normal cells of the same tissue. The invention is directed to antisense oligonucleotides which are complimentary to the coding region of FR.alpha., as well as the pharmaceutical compositions made thereof, and the methods of using the same for treatment of cancers, e.g. cancers of ovary, cervix, uterus, and brain.