EXHIBIT 23 INDEPENDENT AUDITOR'S CONSENT We consent to the incorporation by reference in Registration Statement No. 333-45049 of OSI Systems, Inc. and Subsidiaries on Form S-8 of our report dated September 23, 1999, appearing in this Annual Report on Form 10-K of OSI Systems Inc. and Subsidiaries for the year ended June 30, 1999. Deloitte & Touche LLP Los Angeles, California September 23, 1999 1