SUMMARY In the presence of a linear trend in the population, a slight modification of the usual systematic sampling procedure is found to be highly effective in reducing the error variance of the estimator for the population mean. The efficiency of this modified design in the presence of certain trends, other than linear, such as 'random', 'quadratic' and 'periodic' trends, has been evaluated in comparison with usual systematic sampling methods. The adaptability and suitability of the modified systematic sampling procedure has been illustrated by its application to a survey for estimating the milk yield.