Oligonucleotides directed against the Ha-ras gene are provided for modulating the expression of Ha-ras. The compositions comprise oligonucleotides, particularly antisense oligonucleotides, targeted to nucleic acids encoding the Ha-ras. Methods of using these compounds for modulation of Ha-ras expression and for the treatment of diseases associated with either overexpression of Ha-ras, expression of mutated Ha-ras or both are provided. Examples of diseases are cancer such as lung, breast, colon, prostate, pancreas, lung, liver, thyroid, kidney, brain, testes, stomach, intestine, bowel, spinal cord, sinuses, bladder, urinary tract or ovaries cancers. The oligonucleotides may be composed of deoxyribonucleosides or a nucleic acid analogue such as for example locked nucleic acid or a combination thereof.