The purposes of this study in children who underwent a cycle of myelosuppressive chemotherapy were to describe changes in symptom occurrence and severity during the chemotherapy cycle. Patients (N = 66) 10 to 18 years of age completed the Memorial Symptom Assessment Scale for 10- to 18-year-olds (MSAS 10-18) at the start of a chemotherapy cycle (T1) and weekly for the next 2 weeks (T2 and T3). More than 30% of children reported 10 or more symptoms at all 3 time points. Symptom occurrence trajectories were tested with multilevel logistic regression. In all, 6 symptoms (ie, fatigue, sadness, irritability, worrying, weight loss, sweating) showed a decreasing linear trend. Significant quadratic patterns of change were found for feeling drowsy, nausea, and vomiting. Changes in symptom severity over time were evaluated with multilevel negative binomial regression. No significant differences over time were found in any of the symptom severity scores on the MSAS. Children experienced a high number of symptoms at the initiation of a chemotherapy cycle that persisted over the subsequent 2 weeks.