Under the Constitution of Pakistan, the taxation of agricultural crop incomes is a provincial subject. Although legislation for the taxation of agricultural incomes has been in place in the provinces since 1996/97, actual collection is insignificant. In 2009/10, the provincial governments collected Rs1.2 billion under the budget headings ‘taxes from agriculture’ and ‘agricultural income tax’, of which Punjab’s share was Rs1 billion. These agricultural taxes constituted 2.2% of the provincial tax revenues and 0.22% of the total direct tax revenue in the country. However, in practice, the ‘tax on agriculture’ is a land tax and not an income tax. A recently proposed constitutional amendment by the Senate to bring agricultural incomes under the federal government’s purview mentions a figure of Rs200 billion as the potential tax revenue from agricultural incomes. This paper attempts to quantify the potential tax revenue from crop farming in the province of Punjab, which accounts for over 65% of the production of most major crops in Pakistan. Our estimates suggest that, had the tax been in place in the tax year 2010, the tax revenues from crop farming in Punjab would have been between Rs55 billion and Rs75 billion, assuming small and large farmers were equally productive. Since crop farming accounts for 43% of the value-added in agriculture while livestock accounts for another 54%, our tax estimates – based on crop farming – underestimate the full potential. The paper concludes broadly that, although the perception concerning agricultural income tax potential is exaggerated, its revenue potential is still very large relative to the actual tax collected by the provinces. Taxing this source of income at rates applicable to similar incomes in other sectors of the economy would not only supplement the finances of the provincial governments, but also have an important symbolic value in terms of fairness and equity.