Agricultural workers are often exposed to high levels of dust during field operations. A systematic exposure assessment of annual task-weighted exposure has not been thoroughly examined. The occupational dust exposure in two wine grape vineyards was measured. Exposure levels to total and respirable dust were determined for a 1-year cycle of work. An operation profile including the frequency of tasks was established. The means of total and respirable dust exposure were $1.08;mg/m^3$ and $0.07;mg/m^3$, respectively. Based on the exposure for each task and the task frequency, task-weighted mean exposures to total and respirable dust were estimated as $1.115;mg/m^3$ and $0.079;mg/m^3$, respectively. The task-weighted exposure was significantly represented by three operations and could be attributed to the exposure frequency rather than the exposure intensity of operations. The measurement of a few of the most frequent tasks may be an alternative method of estimating task-weighted exposure. Agricultural dust exposure can be significantly reduced by targeting those tasks most important to task-weighted dust exposure.