Milk samples collected for analysis in the South African Milk Recording Scheme are routinely preserved by the addition of potassium dichromate. The influence of this preservative, the duration of storage temperatures (O °C or room temperature) and effect of temperature prior to readings on the iodine levels of such milk samples was investigated. The only significant finding was that iodine levels declined (P<0,01) in milk samples stored at room temperature for extended periods. The results show that milk samples collected for the Recording Scheme may be used for electrometric iodine determinations as a practical screening technique for milk, but care should be taken to avoid contamination of the samples with iodophor teat dips and other sources of iodine contamination.