Background and aim: Various immunohistochemical stains are used in pathological diagnosis, but the present method of reading the results is somewhat subjective and has the likelihood of error. We tried immunohistochemical analysis with semiquantitative assays to improve the objectivity in the reading. Methods: We used 44 cases of invasive lobular carcinoma (ILC) and 79 cases of invasive ductal carcinoma (IDC). We read the immunohistochemical stains using a semiquantitative manual counting method (IMT i-Solution, ver. 7.5). The immunohistochemical results of estrogen receptor (ER), progesterone receptor (PR), p53 and Ki-67 labeling index were correlated with the tumor grade, tumor size and metastasis. Results: ER, PR and p53 had statistically significant correlation with the tumor grade for IDC. The Ki-67 labeling index had positive correlation with the tumor grade and tumor size for IDC. The ILC showed no such relations, except for the relationship between the Ki-67 labeling index and the nuclear grade. Conclusions: The results of the correlations were similar to the previous studies which had been using the subjective reading method. We think that the semiquantitative reading method is reliable, can overcome the possibility of subjective interpretation errors and allows a numerical report system.