Julian F Guest,1,2 Diana Weidlich,1 Maciej Kaczmarski,3 Elzbieta Jarocka-Cyrta,4 Natalia Kobelska-Dubiel,5 Agnieszka Krauze,6 Iwona Sakowska-Maliszewska,7 Anna Zawadzka-Krajewska8 1Catalyst Health Economics Consultants, Northwood, Middlesex, 2Faculty of Life Sciences and Medicine, King’s College, London, UK; 3Department of Pediatrics, Gastroenterology, and Allergology, Medical University of Bialystok, BiaÅ‚ystok, 4Uniwersytet WarmiÅ„sko‑Mazurski, WydziaÅ‚ Nauk Medycznych, Katedra Pediatrii Klinicznej, Olsztyn, 5Department of Pediatric Gastroenterology and Metabolic Diseases, PoznaÅ„ University of Medical Sciences, PoznaÅ„, 6Klinika Pneumonologii i Alergologii Wieku DzieciÄ™cego, Warsaw, 7Poradnia Gastroenterologiczna Centrum Pediatrii, Sosnowiec, 8Department of Pediatric Pneumonology and Allergology, Medical University of Warsaw, Warsaw, Poland Objective: To estimate the cost-effectiveness of using an extensively hydrolyzed casein formula (eHCF) containing the probiotic Lactobacillus rhamnosus GG (eHCF + LGG; Nutramigen LGG) as an initial treatment for cow’s milk allergy compared with eHCF alone and amino acid formulas (AAF) in Poland from the perspective of the Polish National Health Fund (Narodowy Fundusz Zdrowia [NFZ]) and parents. Methods: Decision modeling was used to estimate the probability of cow’s milk allergic infants developing tolerance to cow’s milk by 18 months. The model also estimated the cost to the NFZ and parents (Polish Zloty [PLN] at 2013–2014 prices) for managing infants over 18 months after starting one of the formulas as well as the relative cost-effectiveness of each of the formulas. Results: The probability of developing tolerance to cow’s milk by 18 months was higher among infants who were fed eHCF + LGG (0.82) compared with those fed eHCF alone (0.53) or an AAF (0.22). An infant who is initially managed with eHCF + LGG is expected to consume fewer health care resources than infants managed with the other formulas. Hence, the estimated total health care cost incurred by the NFZ for initially feeding infants with eHCF + LGG (PLN 5,693) was less than that of feeding infants with eHCF alone (PLN 7,749) or an AAF (PLN 24,333). However, the total cost incurred by parents for initially feeding infants with an AAF (PLN 815) was marginally less than that of feeding with eHCF + LGG (PLN 993), which was less than that of feeding with eHCF alone (PLN 1,226). Conclusion: Using eHCF + LGG instead of eHCF alone or an AAF for first-line management of newly diagnosed infants with cow’s milk allergy affords a cost-effective use of NFZ-funded resources, since it improves outcome for less cost. Whether eHCF + LGG would be viewed as being cost-effective by parents is dependent on their willingness to pay an additional cost for additional tolerance acquisition to cow’s milk. Keywords: amino acid formula, cost-effectiveness, cow’s milk allergy, extensively hydrolyzed formula, Lactobacillus Rhamnosus GG, Poland