In this study wool follicle characteristics of Iranian sheep breeds were investigated. A total of 242 male and female sheep of different age from 5 breeds were studied. Samples of skin were taken from the right midside to determine follicle characteristics. Overall averages for males and females were $3.7{pm}0.1$ and $3.5{pm}0.1$ for S/P ratio; $3.2{pm}0.1$ and $3.6{pm}0.1$ for primary follicle density; $12.1{pm}0.7$ and $13.8{pm}0.4$ for secondary follicle density; $15.3{pm}0.7$ and $17.4{pm}0.4$ for total primary plus secondary follicle density; $2.3{pm}0.2$ and $3.5{pm}0.3$ for percentage of inactive secondary follicles. Significant differences were found in some follicle characteristics between sheep breeds. Results of this study showed that sheep breeds raised in different parts of Iran characterized by a low S/P ratio and follicle density could be classed as carpet wool breeds.