This chapter will present the various international concept on work related income,adopted by the ICLS since 1966. For each concept, the chapter will have a short presentation of their uses,the operational definition,their worker coverage,the recommended reference periods,sources of data collection,etc. The concepts covered are : Wage rates and Earnings(adopted by the 12 th ICLS in 2013 in 1973),Labour Cost (adopted by the 11 th ICLS in 1996),Income related to paid employment (adopted by the 16 th ICLS in 1998),Employee income (adopted by th 17th ICLS in 2003 as part of its definition of household income). the chapter will briefly related these concepts with other international concepts of income, such as Household income (adopted by the 17th ICLS), SNA income(Mixed income,Compensation of employee).