Blood variables are an important tool when assessing the health and welfare of working horses. Commonly, reference intervals established abroad for Thoroughbreds are used, which not necessarily apply for local conditions. Thus, the aim of this study was to establish haematological and biochemical reference intervals for apparently healthy working horses under Chilean local husbandry conditions, and compare them with those proposed in the literature. A group of 320 working horses were sampled, and reference intervals were calculated for 11 haematological and 15 serum biochemical variables according to IFCC (International Federation of Clinical Chemistry) standards. The reference intervals calculated were then compared with those established in the literature for sport and working horses. The percentage of horses below and above the reference intervals from the literature was also calculated. Reference intervals for red blood cell count, haemoglobin and haematocrit were lower for 92.6%, 34.7% and 62.4% of Chilean working horses respectively when compared to reference intervals for UK horses. On the other hand, enzyme reference intervals were higher for CK, LDH and AST, and were higher for 100%, 94.9% and 70.6% of Chilean working horses when compared to reference intervals for UK horses. In conclusion, results show that reference intervals established overlap with those from the literature. The main differences were found when comparing the reference values with those established for sport horses such as Thoroughbreds, whereas values adequate better to those established for working horses in Pakistan.