In 2020 SMC was implemented in 17 out of 33 prefectures, which include 50% of the population outside the city of Conakry. The COVID-19 pandemic, and the presidential elections in Guinea, could potentially have affected SMC campaigns in 2020, it was therefore important to evaluate coverage of SMC given these challenges and the increased area of implementation. The survey took place from 20 Dec 2020 to 4 Jan 2021. All children aged 3 months to 7 years were included in order to determine coverage in the target age group (aged at least 3months at the time of treatment, and aged not more than 59 months at cycle 1) and to determine the proportion of children above the recommended age limit who received treatment. Caregivers were asked about the process of SMC administration, to recall which months their child had received SMC treatments, and about adherence and reasons for any missed doses. Dates of treatments were recorded from the SMC card, and SMC registers were checked to verify SMC treatments for children who did not have a card for inspection during the survey, and for subset of children with cards. In addition, all persons who slept in the household the night before the survey were listed, all bednets owned by the household were also listed and inspected, and for each person, the net they slept under, if any, was noted. A total of 2,447 children eligible to receive 4 treatments were surveyed in 90 clusters. A total of 1374/1521 of households agreed to participate, a response rate of 90.3%. 465 children too old to be eligible for SMC, were also surveyed. Use of LLINs was assessed for a total of 7,028 household members. Cycle 1 took place in July, cycle 2 in August, cycle 3 in September and cycle 4 in October. The median interval between treatments, based on dates recorded on SMC cards, was 33 days between cycle 1 and cycle 2, and 32 days between cycle 2 and 3, and 32 days between cycles 3 and 4. Children aged 3 to 59 months at the time of cycle 1 were eligible to receive SMC four times, and should receive all of these treatments to maximise their protection. Overall, the percentage of eligible children who received SMC was 78.2% in cycle 1, 79.9% in cycle2, 77.4% in cycle3, and 77.2% in cycle 4. Children who did not receive SMC in cycle 1 tended not to receive SMC in later cycles. A total of 17.6% of children did not receive any SMC treatment in 2020, and 70.8% of eligible children received four monthly treatments. SMC was equitable with similar coverage in boys and girls and according to caregiver wealth based on ranking according to household assets. In 99.5% of treated children, the first dose was directly observed, either administered by the CHW (87.4%) or by the caregiver in the presence of the CHW (12.2%). In a small number of cases, (0.5% of children) the blister pack was left with the caregiver to administer later, not observed by the CHW. Reported adherence to the unsupervised doses of amodiaquine was very high. Of eligible children treated at cycle 4, caregivers reported that 96.8% received all three daily doses. Public information campaigns appeared successful, 93.6% of households were aware of SMC and 92.1% said they knew in advance the date of the last campaign. Caregivers were asked if they understood key aspects of SMC, they scored 66% overall on a 10-point questionnaire. Most caregivers (77%) knew that SMC is used to prevent malaria and most (76%) knew that there are 2 tablets to be taken on the first day and one on each of the next two days (85%). However there was a widespread view that SMC drugs could be used for treatment if there was someone unwell in the household (only 36% of caregivers gave the correct response, that SMC drugs should not be used in this way), and only 63% of caregivers appreciated the importance of completing the 3-day course of treatment. In the 2018 SMC survey, 30.2% of children slept under a LLIN the night before the survey. In the 2019 survey, following a mass distribution campaign, this increased to 86% of children. In the 2020 survey, this had fallen to 66% of children under 5 slept who under an LLIN the night before the survey. Children above the age of 5 were less likely to use an LLIN than children under 5. This drop in LLIN use above the age of 5 was more marked in some areas than others. The percentage of the 5-9 age group that slept under an LLIN was only 54%. Of 1,377 households surveyed, 73.5% had at least one LLIN and 23.4% had one LLIN for every 2 persons. This compares with 89.8% had at least one LLIN and 36.8% had one LLIN for every 2 persons in the household, in 2019. Access to a LLIN, the percentage of the population who could sleep under a LLIN if there were two people per net, was 25.4% in 2018. This increased to 68.2% in 2019, and decreased 52.3% to the current survey. 61% of household members slept under an LLIN. High SMC coverage has been maintained in 2020 despite the challenges of delivery during the COVID-19 pandemic.