Abstract: In this study, a thresholding technique was proposed as a mechanism to recognize the malignant cells in epithelial tissues. This is particularly useful for cancer cells diagnosis. Malignant transformation is a genetic operation that causes changes in cells morphology and behavior. Therefore, the evaluation of changes in the cell biology was studied in a way to find out the basis for diagnosing such diseases. The proposed thresholding technique depends on the automation of counting black to white cells ratio and the number of cells in the epithelial tissues samples. This technique has many features, such as: it is able to test hundreds of samples in a less computing time and can provide reliable results and it can give the user a better control over the counting process and can process any part of the sample. The results obtained in this study confirmed the potential of the proposed technique, such that it can judge the malignant cells in epithelial tissues whether normal, abnormal or suspected only in few seconds. Using threshold technique in diagnosing epithelial tissues samples can provide fast and easy way to perform malignant diagnosis (normal, abnormal or suspected) to be used as reference for early diagnosis medical research.