BackgroundThis study assessed staple food price volatility, food consumption scores (FCS) and prevalence of household food insecurity (HHFI) and its socio-inequalities during enforcing and lifting corona virus disease -2019 (COVID-19) lockdown in Nansana municipality, Uganda.MethodsA repeated households (HHs) based cross-sectional study was conducted in urban Nansana Municipality, Uganda. A total of 405 HHs (205 slum and 200 non-slum) were selected using stratified random sampling. Data on social demographics and FCS in the previous 7 days were collected using questionnaire-based telephone interviews with HH heads. Prices for staple foods was collected by asking food sellers from local markets. Mean staple food price differences between before COVID-19 lockdown and during enforcing or lifting the lockdown was tested by paired t test. A binary outcome of HHFI (FCS of 0-35) and food secure (FCS>35) HHs was created. The association between exposure variables and HHFI was tested using multivariate logistic regression analysis at a probability value of 5%.ResultsMean price of staple food significantly increased between before and during enforcing the COVID-19 lockdown (p <0.0001). Mean FCS during COVID-19 lockdown were at borderline for either slum (22.8) or non-slum (22.9) HHs, and were not significantly different from each other (p=0.06). During partial lifting of the lockdown, FCS among slum HHs were significantly lower at 20.1 (poor) compared to non-slum HHs at 22.7 (borderline) (p=0.01). The mean FCS was significantly higher at borderline (24.5) among HHs that received food aid compared to poor FCS (18.2) among slum HHs that did not receive food aid (p<0.0001). The prevalence of HHFI was high and not significantly different (p>0.05) between slum (94.6%) and non-slum (93.5%) HHs during COVID-19 lockdown. HHFI was higher in slum (98.5%) than non-slum (94%) HHs (p<0.05) on partial lifting of the lockdown. Adjusted odds ratio (AOR) showed that being a wage earner and employed HH head was positively (AOR: 8.3, 95% CI: 1.9-36.2) and negatively (AOR: 0.07, CI: 0.02-0.2) associated with HHFI, respectively. During partial lifting of COVID-19 lockdown, slum HHs (AOR: 11.8, 95% CI: 1.5-91.3), female headed HHs (AOR: 11.9, 95%CI: 1.5-92.7), wage earners (AOR: 10.7, 95% CI: 1.4-82.9) and tenants (AOR: 4.0, 95% CI: 1.1- 14.7) were positively associated with HHFI. Conclusion Staple food prices increased during enforcing COVID-19 lockdown compared before lockdown. Food aid distribution during COVID-19 lockdown improved FCS among slum HHs, however, it did not prevent against slum HHFI.