The probe of study is to examine and test Kaldor’s first growth law insights on the inter-temporal causal relationship between agricultural sector growth and economic growth in Kenya. This study employs bounds testing approach to cointegration method known as ARDL (autoregressive distributed lag) and Granger causality test. The empirical results reveal agricultural growth is a causal effect to economic growth and also economic growth is a causal effect to agricultural growth, both in the long-run relationship. This is a comforting result for agricultural economists because it validates the standard policy recommendations aimed at stimulating growth and development through expansion of agriculture.