Development of an automatic system for urine analysis is described. A bench-top’instrument will simultaneously perform seven chemical tests and give a value for the specific gravity of urine specimens, at a sample rate of 120specimens per hour. Reagents packaged in a unique reagent cassette are used for protein, glucose, ketone, pH, occult blood, and bilirubin, and the falling drop method is used to determine specific gravity in this discrete microsampling, multichannel analyzer. A digital, dual wavelength, ratio-reading spectrophotometer for use with surface reactions permits high reproducibility. The total system design includes positive patient-sample identification, central digital programming of all dispense, read-andcompute functions, a digital processor for automatic two-point calibration of each of the channels, decoding in the “plus” system and printout on the sample tag, and the electronic interface with American Standard Code for Information Interchange output for teletype and (or) computer compatibility.