Information about the income distribution in pre-industrial societies is sparse. We analyze labor income inequality in 18 th century Murcia, a city in Mediterranean Spain. The historical income distribution of this region is relatively unknown, despite it having on of the highest urbanization rates in Europe in the pre-industrial era. We first use a census conducted in the 1750s which collected information on income and occupation. We then use this income information to conduct analyses of the income distribution in the 1730s and 1780s using censuses with information about the occupational distribution. We find large changes in the distribution of occupations across the censuses. We show that our results on inequality are sensitive to assumptions regarding household composition and within-occupation distribution of income, but not to the definition of household income.