IN 1974, THE CALIFORNIA SUPREME COURT RULED THAT THE STATE WAS REQUIRED TO PRESERVE THE AMPOULES USED IN THE BREATHALYZER TEST TO ALLOW DEFENDANTS THE OPPORTUNITY TO CONDUCT AN INDEPENDENT ANALYSIS. SINCE THAT DECISION, SEVERAL STATES HAVE MADE THEIR OWN CONTRIBUTIONS TO THE QUESTION OF WHETHER TO PRESERVE BOTH THE BREATH AND THE AMPOULE. THE SEMINAL CASES IN THE AREA OF THE STATE'S DUTY TO DISCLOSE EVIDENCE ARE BRADY V. MARYLAND (1962) AND UNITED STATES V. AGURS (1976). THE REQUIREMENT THAT THE EVIDENCE BE FAVORABLE TO THE ACCUSED AND THE REQUIREMENT OF MATERIALITY ARE ISSUES THAT HAVE BEEN CONSIDERED BY THE COURTS. BECAUSE THE EVIDENCE WOULD NOT BE FAVORABLE TO THE ACCUSED OR MATERIAL TO HIS DEFENSE, THE BRADY DECISION DOES NOT REQUIRE THAT THE STATE PRESERVE THE AMPOULE FOR RETESTING BY THE DEFENDANT. THE FIRST MAJOR CASE TO HOLD THAT THE STATE IS REQUIRED TO SAVE THE AMPOULES WAS PEOPLE V. HITCH (1974). A VARIATION OF THE PRESERVATION OF THE AMPOULES IS PRESERVATION OF A SAMPLE OF THE BREATH ITSELF. COURT DECISIONS REGARDING THE PRESERVATION OF BREATH ARE CITED. THE PAPER CONCLUDES THAT IF THE RATIONALE OF THEORETICAL MATERIALITY IS ACCEPTED WITHOUT LIMITATION, ITS LOGICAL EXTENSION EVENTUALLY WOULD BE THE REQUIREMENT THAT EVERYTHING HAVING TO DO WITH THE TEST BE PRESERVED AND DISCLOSED TO THE DEFENDANT. HOWEVER, THIS WOULD NOT BE FEASIBLE, NOR IS IT REQUIRED UNDER DUE PROCESS. THE REASONABLE METHOD WOULD NOT REQUIRE THE PRESERVATION OF AMPOULES USED IN THE BREATHALYZER TEST. A LISTING BY STATE OF MAJOR BREATHALYZER CASES IS APPENDED, AND FOOTNOTES ARE INCLUDED.