We reviewed 20 years (from 1972 to 1992) of screening for galactosaemia in Ireland. We looked at a small group of 32 patients followed up in the same centre since diagnosis. 1.2 million babies have been screened with 55 cases of classical galactosaemia and 7 Duarte Variants being detected. The frequency is thus, 1:23,000 and is increased among itinerants to 1:700. The mean age of diagnosis was 6.9 days with 41/62 cases symptomatic at the time. There were 9 deaths, 8 in the first 10 years, six of whom were itinerants. On follow up of the 32 children, who have attended Temple Street Hospital, 13/32 have no detectable complication. Nineteen show either one or a combination of cataracts, speech problems, tremors, abnormal FSH and or LH, delayed mental development and recurring infections. The screening test is the Bacterial Inhibition Assay with Beutler test, an original blood spot as confirmation in presumptive possible cases. The Beutler test is performed urgently in high risk situations. Five classical galactosaemics gave false negative results, 3 because of poor feeding, and two because of soya milk formulas. Screening prevented deaths as 7/84 siblings of our cases were unexpected infant deaths, all but one predating screening. Unexplained delay in screening undermines its effectiveness. Survival is enhanced by aggressive neonatal care. Symptoms are improved on commencing diet, with cataracts regressing. Complications did not correlate with the day of starting diet. Galactose-1-Phosphate and urinary galactitol levels did not correlate with complications, but slit lamp examination has proved a helpful index of adherence to diet. The mechanism of complications is unclear, and it is essential that current research should be aggressively pursued to explain mental deficiency in cases treated either pre-natally or early in post natal life.