Abstract: Methods are provided for determining the oncogenic potential of chemical compounds which utilizes a transgenic mouse predisposed to T-cell lymphomas. The transgenic mouse expresses a pim-1 oncogene and as a consequence is predisposed to the spontaneous onset of T-cell lymphomas. The oncogenic potential of a chemical compound is determined by administering a known dose of the chemical compound of interest to a pim-1 transgenic mouse. Thereafter, the transgenic mouse is monitored to detect the onset of a T-cell lymphoma. The time of onset of the T-cell lymphoma and the dosage of the chemical compound are compared to either the onset of spontaneous T-cell lymphomas in the pim-1 transgenic mouse or to the onset of a T-cell lymphoma in a pim-1 transgenic mouse which has been exposed to a known quantity of a carcinogenic agent. This provides an indication of the oncogenic potential of the chemical compound.