To compare the effectiveness and acceptability of a newly developed pediatric sialometer as an alternative to the conventional spitting method. A clinical study was carried out with healthy children (G1; n = 30) and oncological children (G2; n = 30). A newly developed pediatric sialometer was compared to the traditional spitting method to determine unstimulated salivary flow (mL/min), with a one-hour wash out period between sample collections. A semi-structured questionnaire was applied to G1 and G2 using the Facial Anxiety Scale to evaluate the device’s acceptability. The children’s behavior was also observed throughout saliva collection. The data were analyzed by Mann-Whitney U, Wilcoxon, Student’s t and Chi-Square tests (α = 5%). There was no significant difference between groups and methods (P > 0.05). However, the saliva collected with the pediatric sialometer was clearer and had less apparent contamination. The device characteristics were rated positively, with high acceptability even among children with more difficult conditioning (G2) (P > 0.05). The newly developed pediatric sialometer presented herein can be an alternative option for saliva collection in pediatric dentistry, with good reproducibility and acceptability by children.