Long-lasting insecticide-treated nets (LLITNs) are expected to be an important advance in malaria control, but operational experience is still scarce. This study presents some operational findings concerning the introduction of Olyset LLITNs (Sumitomo Chemical Co., Ltd, Japan) in Laos. The study site, Bourapar district, a remote district at high risk of malaria, received Olyset nets during 1999-2000. After distribution of the nets the number of malaria cases in the district hospital decreased for a time, however it began to rise again a year after the intervention. To sustain the effect of the nets, net users were given instructions on maintenance and use. This study aimed to investigate the condition of Olyset nets and the maintenance behaviour of net users after 2-3 years of use, and to examine the associations between maintenance behaviour and the number of malaria episodes during the previous year. Questionnaire interviews and inspections of nets were conducted at 240 households during February-March 2003. About 40% of the observed nets had holes/were torn, and the maintenance instructions had not been followed sufficiently. Households following the recommended washing frequency (38.2%) reported fewer malaria episodes during the past year, which demonstrates the importance of the recommended washing frequency in the effective use of the nets. Our study promotes the idea that, in addition to pursuing high coverage of LLITNs, more effort should be made to ensure that nets are kept in good condition in future LLITN programmes.