Background: In Yemen there are only a few special epidemiological studies dedicated to malignancy, and for this motivation it is necessary to strengthen, update, construct and continue to afford studies on tumor comportments with the plan of achieving better influence on public health, with early diagnosis and suitable treatment with the plan of enhance survival of living and reducing the feasible subsequent consequences of malignancy. Aims: The study designed to illustrate the different types of kidney cancer (KC), the gender and age distribution of the cancer, and to identify the different types of them and their correlation with invasion and gradation; and its association with age groups and gender. Materials and methods: A retrospective observational study was performed on renal masses patients who were consequently diagnosed selectively by histopathological study in the National Center for Public Health Laboratories (NCPHL) at the Department of Pathology, and the Department of Pathology in Al-Thorah university hospital, Sana'a, Yemen, over a period of 18 years from January 1, 2004 to December 31, 2021. Data were collected from hospital records. The study variables were lesions histological types, benign, malignancy, non-neoplastic lesions, sex, grades and age. The whole data were analyzed by IBM SPSS Statistics 22.Ink. The outcomes for variables were given in the form of rates (%). Chi Square was used for categorical variables that measured association among categorical variables. P-values less than 0.05 were considered significant. Results: Malignant tumors accounted for 177/282 (62.8%) of the total kidney lesions, renal cell carcinoma (RCC) was the most common type of cancer with 126/282 (44.7%), followed by Wilms tumors 47/282 (16.7%), while non-Hodgkin’s lymphoma reported 3 cases (1.1%) and mucinous carcinoma one case (0.35%). Benign tumors accounted for 14/282 (5%), and non-neoplastic lesions accounted for 91/282 (32.3%). Concerning RCC, the average diameter of RCC is 8.9 cm. GI 40/126 (31.7%) with mean tumor diameter equal to 5.8 cm; GII was the most frequent grade 63/126 (50%). Conclusion: Renal cell carcinoma in Yemeni adults presents at an early age with an increased incidence among the female sex with a relatively larger tumor size. It appears that there has been a slight improvement in the diagnosis of kidney cancer in Yemen over the past 18 years. Peer Review History: Received: 4 March 2022; Revised: 12 April; Accepted: 28 April, Available online: 15 May 2022 Academic Editor: Dr. Jennifer Audu-Peter, University of Jos, Nigeria, drambia44@gmail.com UJPR follows the most transparent and toughest ‘Advanced OPEN peer review’ system. The identity of the authors and, reviewers will be known to each other. This transparent process will help to eradicate any possible malicious/purposeful interference by any person (publishing staff, reviewer, editor, author, etc) during peer review. As a result of this unique system, all reviewers will get their due recognition and respect, once their names are published in the papers. We expect that, by publishing peer review reports with published papers, will be helpful to many authors for drafting their article according to the specifications. Auhors will remove any error of their article and they will improve their article(s) according to the previous reports displayed with published article(s). The main purpose of it is ‘to improve the quality of a candidate manuscript’. Our reviewers check the ‘strength and weakness of a manuscript honestly’. There will increase in the perfection, and transparency. Received file: Reviewer's Comments: Average Peer review marks at initial stage: 6.0/10 Average Peer review marks at publication stage: 7.0/10 Reviewers: Eyassu Mathewos Oridanigo,Department of Nursing, College of Medical and Health Sciences, Wachemo university, Durame Campus, Durame, Ethiopia, eyumathi@gmail.comDr. Vanina Doris Edo’o, University of Yaounde I, Yaounde, Cameroun, vanina_edoo@yahoo.com Similar Articles: SIDE EFFECTS OF CYCLOSPORINE COMPARED TO TACROLIMUS AMONG YEMENI KIDNEY TRANSPLANT PATIENTS WHO SHARE THE SAME ADJUVANT AGENTS: MYCOPHENOLATE MOFETIL AND PREDNISONE MOST IMPORTANT CELLULAR CHANGES INVOLVED IN RENAL ISCHEMIA REPERFUSION INJURY AND THE CONSEQUENT IMPACT ON SELECTED REMOTE ORGANS