Background: Hemodialysis (HD) and peritoneal dialysis (PD) are medically equivalent alternatives for symptomatic therapy of end-stage renal disease (ESRD). An early referral (ER) of patients with chronic kidney disease (CKD) to a nephrological specialist is associated with a higher proportion of patients choosing PD. Germany historically shows a low PD uptake. This article is the first investigation into the impact of ER on the uptake of PD, using a large German claims database. Methods: Claims data of 4727 incident dialysis patients in 2015 and 2016 were analyzed. Accounting codes for nephrological care and dialysis modalities were identified. Their first documentation was defined as their first encounter with a nephrologist and their first dialysis treatment (HD or PD). ER was determined as receiving nephrological care at least six months before the first dialysis. A multivariate logistic regression model with adjusted odds ratios (AOR) investigates the impact of ER, outpatient dialysis start, age, comorbidities, and sex on the chance for PD. Results: Forty-three percent were referred to the nephrologist six months before their first dialysis (ER). Single tests, as well as the adjusted multivariate logistic regression, highlighted that ER significantly increases the chance for PD. In the multivariate model, the uptake of PD was associated with ER (AOR = 3.05; p < 0.001; 95% CI = 2.16–4.32), outpatient dialysis start (AOR = 0.71; p = 0.044; 95% CI = 0.51–0.99), younger age (AOR = 0.96; p < 0.001; 95% CI = 0.95–0.97), and fewer comorbidities (AOR = 0.85; p < 0.001; 95% CI = 0.44–1.58). Conclusions: ER of patients with CKD to a nephrologist increases PD uptake. It gives both nephrologists and patients enough time for patient education about different treatment options and can contribute to informed decisions about the dialysis treatment.