ObjectiveParents and health professionals believe that recurrent respiratory tract infections (RRTI) have a large impact on children with Down syndrome (DS). We studied the relation between parent‐reported RRTI and development, behaviour and health‐related quality of life (HRQoL) in 8‐year‐old children with DS.MethodDuring a 3‐year period, 325 children with DS were recruited for inclusion in this observational study. Parents were asked to fill in the Child Behavior Checklist and TNO‐AZL Children's Quality of Life Parent Form. A psychological assistant administrated the McCarthy Scales of Children's Abilities. The children were divided into a group with presence of RRTI (RRTI +) and a group without RRTI (RRTI −), on the basis of parental report. Linear regression analyses were performed to assess the effect of RRTI, while correcting for the influence of confounders.ResultsCompared with RRTI − children (n = 176), RRTI + children (n = 149, 46%) showed decreased mental and motor development (mean developmental age 3.67 vs. 4.08 years), more behavioural problems and lower scores on most HRQoL scales (P < 0.05). Moreover, school enrolment is less favourable in RRTI + children.ConclusionIn 8‐year‐olds with DS, the children with parent‐reported RRTI show more delayed development, more behavioural problems and lower HRQoL compared with the children without RRTI. Although this association does not prove a causal relationship, further studies should focus on this, because RRTI are potentially preventable.