Aims This work aimed to assess the salivary and urinary levels of nickel and chromium ions in children with stainless steel crowns and band and loop space maintainers. Settings and design The study was conducted as a clinical trial. The clinical part was carried out at Pediatric Dentistry Department, Faculty of Dentistry, Tanta University and the laboratory work was carried out at Biochemistry Department, Faculty of Medicine, Tanta University. Patients and methods Sixty children of both sexes aged between 5 and 8 years old were included in the study. The selected children were divided into two groups; group 1 included 30 children received stainless steel crowns and group 2 included 30 children received band and loop space maintainers. Salivary and urinary samples were collected from the participating children at the beginning of the study and then after 1 week, 2 weeks, 1 month, 3 months, 6 months and 9 months of receiving the appliances. The samples were prepared and analyzed for measuring nickel and chromium ions release using inductively coupled plasma optical emission spectrometry. Statistical analysis used All test statistics were performed using the SPSS software statistical package and the significance was set at P value less than or equal to 0.001. Results Salivary metal ions release reached its peak on the first week then diminished with time and urinary release increased on the first week, nearly remained stable till the first month then it decreased with time. Ions levels were higher in urine than in saliva with statistically significant differences. The release is slightly higher in group 2 but without statistically significant differences between both groups. Conclusions The maximum levels of released ions were significantly below their average dietary intake levels and did not reach their upper tolerable intake levels.