Concreting in arid environment is a delicate operation, due to many problems, such as the premature evaporation of mixing water, which affects the material consistency and the shrinkage cracking which threatens its durability. The present experimental work is conducted to investigate the physical and the mechanical behaviour of cement mortar reinforced by recycled polypropylene fibres under arid conditions, at 45 °C and 30% RH. The used polypropylene fibres are recycled from a domestic plastic waste. The tests realized in this investigation include the workability, the total shrinkage, the flexure and the compression tests. Through this investigation, the beneficial effect of recycled polypropylene fibres as reinforcement of cement mortar is well demonstrated, particularly under arid environmental conditions. The obtained results showed a substantial increase in the flow time of about 53% in mortar reinforced by 1% of recycled polypropylene fibres (1RPFM). It is also shown that under arid conditions, the presence of 1% of recycled polypropylene fibres in cement mortar leads to a considerable decrease in total shrinkage of about 46% and an increase in the flexural and compressive strength of about 24% and 26%, respectively, compared to control mortar (CM) at the age of 194 days. Overall, the used recycled polypropylene fibres have presented a high capacity to improve the different properties of cement mortar and make it a suitable composite for concreting in arid environment.