According to the Objective 2021 European Drug report, approximately 4.4 million people use cocaine, and it is the second most commonly used drug in Europe. Despite the alarming developments associated with the pandemic period, the increase in the availability and use of cocaine is remarkable. Recently, many methods have been used in cocaine smuggling, such as impregnation on papers, vegetable-fruit cartons, and clothings. This makes it almost impossible to detect cocaine and similar drugs with handheld devices used at checkpoints at the airport or prison. In this study, it was aimed to evaluate the homogeneity of the paper in order to easily and accurately predict the amount of cocaine impregnated onto the paper. A5 paper paper sheet (80 g/cm 2 ) is divided into 315 (1 × 1 cm 2 ) squares, with 21 rows and 15 columns. Working solution was prepared by dissolving cocaine (0.38 mg) in 500 mL methanol at 760 ng/mL concentration. It was dipped into the working solutions placed in glass containers, and kept in the solutions until it was completely wet. Cocaine-impregnated papers were left to dry for about 1 h at room temperature on a clean flat surface. 1 cm square of paper was removed placed into separate glass 10 × 160 mm glass tubes with 1 mL methanol and coc-d3 (1 ng/mL). Samples were extracted by ultrasonication for 1 h and then centrifuged at 3500 rpm for 10 min. The solvent was evaporated to dryness under nitrogen gas at 40 °C. The dry residues were dissolved in 500 μL mobile phase A. 20 μL sample were injected to LC-MS/MS after they were diluted 1:10 with methanol. During this procedure, blank A5 paper was used as a control. A5 paper sheet absorbed approximately 7.5 mL of cocaine solution. Rows were used as the sample unit while testing homogeneity. Both the short edge of the paper are formed as cluster A and other area cluster B. Heatmap of the quantitative results created. Cluster-B consists of large number of samples (90.4% of all samples) and concentrations had a high variation (between 0.46–1.18). Therefore to decrease bias which will occur with selecting a sample from highly variated population, a second stage clustering analysis was repeated with 19 rows to check whether it was divided into sub-clusters within itself. The highest concentrations were found at the short edge of the paper which first immersed into the solution. Each square absorbed an average of 0.69 ng/cm 2 and was close to the theoretically calculated concentration (0.72 ng/cm 2 ). The mean of the four concentrations which were randomly selected from each created cluster was close to the overall mean of paper's concentration. In order to evaluate the consistency, a sample was taken from each cluster by using the random sampling method, and the mean concentration value was calculated (0.69 ng/cm 2 ). This process was repeated 1000 times. In this study, it was seen that a sample should be taken from at the short edges of the paper and a four pieces should be taken randomly from other parts depending on the size of the paper. To our knowledge, there is no study in the literature on the evaluation of homogeneity of cocaine-impregnated papers. This study will guide forensic chemists and toxicologists in sample selection.