Jan Winberg, Professor Emeritus of Pediatrics at the Karolinska Institute, died at the age of 79 years on 22 February 2003. He was one of the pioneers of pediatric nephrology and an inspiring teacher and leader with a unique scientific and social competence.

He was born in Stockholm in 1923 where he also received his medical training. He started his medical career at the Department of Pediatrics at the Karolinska Hospital. Inspired by clinical problems, he soon became interested in renal function and began his studies focusing on endogenous creatinine clearance and renal concentrating capacity in children. His thesis had the title "Studies of renal function in children with acute urinary tract infection and with obstructive malformations of the urinary tract".

In 1959 he moved to the Swedish west coast as senior lecturer at the Gothenburg Children's Hospital. The Medical Faculty had recently been established and development was rapid. With great enthusiasm, Jan started a large prospective study on urinary tract infections in children, with focus on epidemiological, diagnostic, and microbiological aspects. Full of ideas, with great diplomatic skill, and with cooperation as a leading principle, he created a team involving scientists from various university departments. In addition to abiding by high scientific standards, he created a unique clinical climate, with the sick child and the family always at the center. The project expanded and the results that emerged were of major importance for the understanding of the pathophysiology and management of children with urinary tract infection. He advocated an active search for children with renal infection among those with high fever, and he understood the importance of rapid and adequate management in primary care. It is to his credit that the incidence of long-term complications of urinary infections is very low in Sweden.

By 1968 he had already moved back to Stockholm. A few years later he was appointed professor of pediatrics in Umeå, then in Huddinge, and the circle was completed when he returned as head to the Karolinska Hospital. Wherever he went, Jan Winberg started new projects, built new teams, and raised enthusiasm in new collaborators. He kept in contact with the teams he had left and acted as a mentor in the best sense of the word. He always managed to find the time to discuss problems, scientific as well as clinical. Most of his scientific work concerned urinary tract infections, and especially microbiological aspects, such as the impact of antibiotics on the bacterial flora of the body. His team made significant contributions to the understanding of the mechanisms by which Escherichia coli can attach to epithelial cells within the urinary tract and induce inflammation.

His contribution to the development of the care of children with renal diseases was significant indeed, but this was not his only field of interest. He initiated pioneering work on the importance of breastfeeding as protection against infections, and studied factors that are of importance for the early bonding between mother and child. He also remained actively involved in these scientific projects after his formal retirement. Neither his curious mind nor his bright intellect was impaired by the serious lung disease that took his life, and he remained interested in discussing problems with co-workers even during the last difficult year.

In the international field, Jan was one of the pioneers of pediatric nephrology. He was one of the founders of the European Society for Paediatric Nephrology and he contributed significantly to the development of the International Pediatric Nephrology Association. He was also awarded honorary membership of these organizations.

Although he was a scientific authority, it is above all because of his personal qualities that we remember him. He was generous, had a modest personality, and was always considerate towards all, patients, families, and staff alike. He had a unique ability to spread his enthusiasm amongst his collaborators and he encouraged many medical students to choose a future in pediatrics. Many were inspired by him to work with children and to enter the field of pediatric nephrology. We will greatly miss him.