Establishing a causal relationship between health and productivity is not straightforward. On one hand, higher income individuals invest more in health: as their income grows, they invest in better diets and health care. On the other, if a worker is healthier and more energetic, then she will probably be more productive. This paper focuses on the second pathway and examines the effect of one dimension of health, height and body mass index (BMI), on wages. Data comes from a longitudinal study conducted in Guatemala, a low-income country, during 1969-1977 and followed-up in 2002-2004. The estimates suggest a very non-linear relationship between height, BMI and wages; however, the evidence is stronger for males than for females. While diminishing returns are operating at higher quantiles of the conditional wage distribution, increasing returns appear at lower quantiles, implying that height and BMI might have an increasing payoff for the poorer workers.