Although the inhibitor of apoptosis protein‑like protein‑2 (ILP‑2) has been shown as a serological biomarker for breast cancer, its effect on breast cancer cell growth remains elusive. The present study aimed to determine the role of ILP‑2 in breast cancer cell growth. We used immunohistochemistry to analyze ILP‑2 expression in 59 tissue paraffin‑embedded blocks, which included 35 breast cancer tissues and 24 galactophore hyperplasia tissues. Western blot analysis was used to detect protein expression levels of ILP‑2 in breast cancer cell lines such as HCC‑1937, MX‑1 and MCF‑7 as well as breast gland cell line MCF 10A. ILP‑2 was silenced by siRNA in HCC‑1937, MX‑1 and MCF‑7 cell lines. MTT assays, scratch assays and AO‑EB double staining analysis were conducted to evidence the role of ILP‑2 on breast cancer cell growth. Results from this study showed increased ILP‑2 expression in breast cancer tissues and breast cancer cell lines such as HCC‑1937, MX‑1 and MCF‑7. Cell viability or rate of cell migration of HCC‑1937, MX‑1 and MCF‑7 cell lines was significantly inhibited when ILP‑2 was knocked down by siRNA. The apoptosis rate of HCC‑1937, MX‑1 and MCF‑7 cell lines was increased when compared with that of the control group. Thus, ILP‑2 plays an active role in the growth of breast cancer cells.