The 4T1 murine mammary carcinoma cells have the ability to spread to target organs in BALB/c mice breast cancer model. The spread of 4T1 cells mimics human stage IV breast cancer and elicits immune responses. The aim of this study is to establish an animal model of mammary carcinoma metastasis to discern the in vivo effects of growth and spread of breast cancer. Six-weeks-old female BALB/c mice were inoculated with 4T1 murine breast cancer cells. Gross and histological studies were carried out to determine the approximate day of metastatic onset. Production of IFN-gamma was assessed by ELISA to understand its role in tumour growth and metastasis. Lymphocyte markers such as CD8⁺, CD25 and CD49b were analysed to elucidate its role in tumour growth and progression. The metastatic onset occurs approximately 11 days after inoculation and accompanied with hepatosplenomegaly. The breast cancer cells from primary tumour were found to spread rapidly to the liver on day 11. IFN-γ production was higher in inoculated mice serum compared to control. Higher numbers of CD8⁺, CD25 and CD49b cells were observed in the peripheral blood of inoculated mice, compared to control. In conclusion, the 4T1 murine breast cancer cells can migrate and metastasise rapidly to the liver, eliciting various immune responses.