As of the census of 2000, there were 254 people, 119 households, and 69 families residing in the village. The population density was 97.6 people per square mile (37.7/km²). There were 125 housing units at an average density of 48.0/sq mi (18.6/km²). The racial makeup of the village was 95.28% White, 4.72% from other races. Hispanic or Latino of any race were 7.87% of the population.
The top three ancentries reported in McCook as of the 2000 census were Polish (18.9%), Irish (16.3%) and Italian (16.3%).
There were 119 households out of which 19.3% had children under the age of 18 living with them, 39.5% were married couples living together, 11.8% had a female householder with no husband present, and 42.0% were non-families. 39.5% of all households were made up of individuals and 15.1% had someone living alone who was 65 years of age or older. The average household size was 2.13 and the average family size was 2.86.
In the village the population was spread out with 16.5% under the age of 18, 8.7% from 18 to 24, 28.3% from 25 to 44, 25.2% from 45 to 64, and 21.3% who were 65 years of age or older. The median age was 43 years. For every 100 females there were 91.0 males. For every 100 females age 18 and over, there were 91.0 males.
The median income for a household in the village was $43,125, and the median income for a family was $58,333. Males had a median income of $40,625 versus $26,429 for females. The per capita income for the village was $24,996. None of the families and 1.8% of the population were living below the poverty line, including no under eighteens and 4.1% of those over 64.