An experimental microcomputer-based system has been developed for in-situ, non-destructive measurement of cotton plant morphology. Seven ultrasonic sensors and an ultrasonic ranging module were used to scan the plant row for distance-to-plant measurements at three vertical positions and on the top of the plant row. An incremental optical shaft encoder was used as a position sensor to measure the forward travel distance of the instrument. The selected horizontal interval along the row between sample collections was 31 mm. An interface was designed to connect a single-board computer (SBC) with the ultrasonic sensor system for data acquisition. The storage capacity of this measurement system was 7,000 data values. A key pad was interfaced with the SBC to input the operation commands. A liquid crystal display (LCD) unit was used to display all measurement results, including cumulative plant volume, maximum and average plant widths at the three vertical positions, and maximum and average plant heights.