A simultaneous-equation model containing yellow maize export demand and supply functions was specified and estimated by Two-Stage Least Squares using annual data for the period 1960-1990. Export demand was influenced by the world price (real) of yellow maize and lagged exports. Export supply was explained by the lagged domestic producer price, lagged exports and random shocks in supply. The price elasticity of export demand estimated directly from the model was high (-37.90), but lower than that estimated by Johnson's indirect method (-181.30). Export supply in the short- and long-run was price inelastic and relatively more responsive to supply shocks. These results support a priori expectations that local yellow maize producers are price takers on the world market and that export supply reacts sluggishly to changes in the lagged producer price of yellow maize. Climatic variation was the major determinant of export supply. Implications for future yellow maize export supply of potential world trade liberalisation and niche marketing are discussed.