Purpose: Informal telemedicine consultations via instant messaging apps among physicians pose certain ethical and legal risks. Data regarding its use is scarce. The aim of this study was to assess the extent of use of instant messaging apps as medical consultation platform among pediatricians and its possible risks and benefits.Methods: A prospective cross-sectional study conducted in Israel from August to November, 2019. Data were obtained through questionnaires filled by pediatricians. The frequency of informal consultations, clinical features and recommendations given, were compared according to the pediatrician's expertise (resident Vs specialist) and place of work (hospital Vs community).Results: Three hundred and five pediatricians with a median age of 37 years (range 27-74) filled questionnaires; 129 pediatric residents and 176 specialists. Of them 302 (99.3%) reported giving informal consultations using instant messaging app on a regular basis. The majority (65%) reported 1-5 consultations/week. Certified pediatricians were more likely to give multiple consultations (10 or more/week) compared to residents (24% vs 5.4%, p<0.001), and they were more likely to advice patient for treatment (35% vs. 22%, respectively, p<0.001). Media files were attached in 72% of cases. No disclaimer regarding the risks associated with the informal consultation was added in 33% of the consultations.Conclusions: Informal medical consultation by instant messaging apps is very common, especially among certified pediatricians. The use of attached confidential media is common. Ethical and legal aspects are not fully considered. Guidelines are urgently needed.