Introduction: Pediatric CSVT diagnosis is dependent on neuroimaging (MRV/CTV). Biomarkers to suspect, quantify and prognosticate CSVT are lacking. D-dimer (DD) assay is useful in adults for diagnosis/prognosis.Objectives: To determine frequency of elevated DD and its correlation with clot burden and outcome in pediatric CSVT.Methodology: Children (29-days-18-years) with CSVT and DD assay from Sept’99-Dec’09 were identified. Patients with DD performed <7 before and <14 days after CSVT diagnosis were included. Clinical data, D-dimer (abnormal level: any value > institutional age-specific normative value, ng/mL) and neuroimaging data [high clot burden (>1 sinus with thrombus), hemorrhage, CSVT-propagation, recanalization] were analyzed. Goups were compared by Fisher’s exact/Chi-Square test. Logistic regression was used for outcome prediction.Results: Ninety-three CSVT patients were identified. Sixty had DD. Forty-six (21 males) were included [mean age: 8-yrs, median time (in relation to CSVT-diagnosis) of DD-assay: 4+6.2-days]. DD was elevated in 32/46(70%). No significant differences (with respect to age, gender, clinical/radiological features, risk factors, treatment) were found between those with and without elevated DD, except strong trends with respect to high clot burden [97% with, 79% without elevated DD, (p=0.069)] and CSVT-propagation [25% with, 0% without elevated DD, (p=0.0845)]. Logistic regression analysis revealed 55% and 61% increased likelihood of clot propagation and poor neurological outcome respectively per 1000 unit DD increase.Interpretation: D-dimer level is elevated in most children with CSVT and seems to correlate with CSVT burden, propagation and poor clinical outcome. Larger prospective study is warranted.