Madrid
uses the infolines
outer theme, so you need to redefine the footline
template as implemented for this outer theme; here are the necessary changes:
\documentclass{beamer}
\usetheme{Madrid}
\makeatletter
\setbeamertemplate{footline}
{
\leavevmode%
\hbox{%
\begin{beamercolorbox}[wd=.333333\paperwidth,ht=2.25ex,dp=1ex,center]{author in head/foot}%
\usebeamerfont{author in head/foot}\insertsection
\end{beamercolorbox}%
\begin{beamercolorbox}[wd=.333333\paperwidth,ht=2.25ex,dp=1ex,center]{title in head/foot}%
\usebeamerfont{title in head/foot}\insertsubsection
\end{beamercolorbox}%
\begin{beamercolorbox}[wd=.333333\paperwidth,ht=2.25ex,dp=1ex,right]{date in head/foot}%
\usebeamerfont{date in head/foot}\insertshortdate{}\hspace*{2em}
\insertframenumber{} / \inserttotalframenumber\hspace*{2ex}
\end{beamercolorbox}}%
\vskip0pt%
}
\makeatother
\title{The Title}
\author{The Author}
\begin{document}
\section{Test Section One}
\subsection{Test Subsection One One}
\begin{frame}
test
\end{frame}
\subsection{Test Subsection One Two}
\begin{frame}
test
\end{frame}
\end{document}

[beamer] footline madrid
for a lot of questions similar to this one on TeX.SE search bar. – percusse Nov 17 '12 at 0:13