Cystic fibrosis is one of the most common autosomal recessive mutation in cystic fibrosis transmembrane conductance regulator (CFTR)gene. Like most chronic inflammatory diseases in childhood, CF is associated with impaired growth. The growth hormone insulin-like growth factor (GH-IGF) axis is the most important endocrine axis involved in linear growth in children and adolescents. Aim: To study serum IGF-1 level in cystic fibrosis patients in stable state and in exacerbation and to correlate its level with body mass index of the patients. Methods: This study was conducted on 60 CF patients and 30 healthy age and sex matched children as control group. Anthropometric measurements including height, weight and BMI were recorded, Serum IGF-1 level was performed by using Enzyme Linked Immuno Sorbent Assay (ELISA) technique, complete blood picture and C-reactive protein were done. Results: Our results showed that IGF-1 levels were statistically lower in cases compared to control (p value < 0.01), also IGF-1 levels were significantly lower in exacerbation compared to stable state (p value <0.01) but there was no correlation between IGF-1 and BMI, weight, height and age of the patients. Conclusion: Serum IGF-1 level was noted to be lower in CF cases and especially in CF cases in exacerbation and a significant relation was found between it and the haemoglobin and inflammatory status in CF patients.