Weed infestation is a major problem and matter of concern as it reduces yield as well as quality of many crops including sugar beet. Manual weeding is very tedious, costly, time consuming and most probably non-availability of trained and skillful labor is another issue. Keeping in view these facts, an experiment was performed to evaluate the efficacy of dual gold on the weed biomass (g m-2) and on the growth and yield components of sugar beet (Beta vulgaris L.) cv. California-KWS during 2013-14 and 2014-15. The study was performed using RCBD having five treatments and three replications. The treatments included different application times (pre-emergence application and application after 15, 30 and 45 days after emergence) of dual gold (S-metolachlor) and a control (weedy check). Data were recorded on fresh and dry weed biomasses (g m-2), number of leaves plant-1, leaf area plant-1 (cm2), leaf and root weights plant-1 (g), sucrose (%), TSS (%), root and sugar yields (t ha-1). The results showed significant variation among the treatments for all parameters during both years of study. Among the treatments, the dual gold (S-metolachlor) applied as pre-emergence reduced weed fresh and dry biomasses (g m-2) and also enhanced number of leaves plant-1, leaf area (cm2), leaf and root weight plant-1, sucrose (%), TSS (%), root and sugar yields (t ha-1) during both years. Hence, it is concluded that dual gold (S-metolachlor) applied as pre-emergence is best for eradicating weeds at early stages of growth and hence improving yield and quality of sugar beet under Dera Ismail Khan conditions.