en Original Original <p style="text-align: justify;"><strong>Introduction: </strong>Correct interpretation of kidney images requires the knowledge of its normal&nbsp;size. This study aimed to establish normal values for kidney length and parenchymal thickness&nbsp;and identify the potential related factors in a group of Iranian adults.<br> <strong>Methods: </strong>Renal dimensions, including length and parenchymal thickness were measured&nbsp;by sonography in 103 individuals with no renal disease. Statistical analyses were done to&nbsp;find the effect of different variables such as side, age, and gender using 2-tailed t-test, Mann-Whitney test, paired t test, and Wilcoxon-signed rank test. The correlation of renal dimensions&nbsp;with anthropometric parameters, including weight, height, and body mass index (BMI) was&nbsp;analyzed using the Pearson correlation coefficient.<br> <strong>Results:</strong> Mean (SD) kidney length was 104.96(6.6) mm for the right, and 106.22(6.16) mm for&nbsp;the left kidney (P=0.02). Mean (SD) parenchymal thickness for the right kidney was 16.9(1.6)&nbsp;mm and on the left side, it was 18.2(1.7) mm (P<0.001). Gender related analysis showed&nbsp;significant differences between male and female renal length and parenchymal thickness&nbsp;(P<0.05). Age group analysis regardless of sex showed significant decrease in renal length&nbsp;and parenchymal thickness beyond the fifth decade of life. There was a positive correlation&nbsp;between bilateral renal length and body weight as well as BMI. Also, there was a weak positive&nbsp;correlation with body height.<br> <strong>Conclusion: </strong>Because of several factors affecting on kidney size, its assessment should be made&nbsp;individually. The important influencing factors are ethnicity, gender, age, BMI, and height.</p> Ultrasonography, Biometry, Kidney 25 32 http://anatomyjournal.ir/browse.php?a_code=A-10-125-1&slc_lang=en&sid=1 Mahmoud Jabbari jabbari@umsha.ac.ir 10031947532846003472 10031947532846003472 No Department of Radiology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran. Reza Mollazade rezamollazade@yahoo.com 10031947532846003473 10031947532846003473 No Department of Radiology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran. Farzaneh Esna Ashari esna_f@yahoo.com 10031947532846003474 10031947532846003474 No Department of Social Medicine, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran. Zohreh Alizadeh alizadeh@umsha.ac.ir 10031947532846003475 10031947532846003475 Yes Department of Anatomical Sciences, Endometrium and Endometriosis Research Center, Hamadan University of Medical Sciences, Hamadan, Iran.