BACKGROUND: Generalised aggressive periodontitis (GAP) is a rare condition associated with rapid periodontal destruction, in multiple teeth. The paper aims to present a case of an 8-year old with GAP and discuss his response to treatment. CASE REPORT: An 8-year old male was referred to the postgraduate clinic of paediatric dentistry of the University of Athens due to increased mobility in his primary dentition. At initial clinical examination, plaque accumulation, gingival inflammation and temporary restorations were noted. Detailed periodontal examination revealed bleeding on probing, pocket depths of up to 9 mm and second degree mobility in primary teeth. Radiographic examination showed advanced bone loss and carious lesions. Microbiological analysis revealed increased percentages of peri-opathogens in pooled subgingival samples. Final diagnosis of GAP was made after ruling out any underlying systemic disorder. TREATMENT: Periodontal therapy involved non-surgical subgingival debridement, systemic administration of antibiotics and retention of periodontally involved teeth. FOLLOW-UP: This was based on a monthly recall program for the first 6 months and a 3-monthly regime thereafter. At 18-months after initial examination, a substantial improvement in clinical parameters was seen, while levels of periodontal pathogens were sustained at low levels. CONCLUSION: Non-surgical root debridement along with systemic administration of antibiotics and retention of the periodontally involved teeth, can be successful in achieving improvement and maintenance of periodontal health in the mixed dentition. Key words: Generalised aggressive periodontitis, children, Aggregatibacter actinomycetemcomitans, periodontal treatment, tooth extraction.