The East Carmarthenshire by-election, 1890 was a parliamentary by-election held for the House of Commons constituency of East Carmarthenshire in West Wales in August 1890.
The vacancy resulted from the death of the sitting member, David Pugh, who had held the seat since it was formed in 1885.
David Pugh had announced his intention not to seek re-election some weeks before his death. Therefore moves to select a new candidate were already in place when the vacancy occurred. On July, delegates from the various branches of the Liberal Party on the division met at Llandeilo and it was decided that a series of meetings would be held throughout the constituency to allow the electors to hear the candidates. A large number of candidates were proposed, including Alfred Davies, R.D. Burnie, and the well-known local doctor, Howell Rees.
A number of meetings were subsequently held which gave the candidates an opportunity to address the electors. Within a few days all had withdrawn with the exception of Gwilym Evans and the Swansea-based lawyer, Abel Thomas. It appeared that Evans was largely supported by the more industrialised parts of the community while Thomas drew most support from the rural areas.
At these meetings, both candidates expressed support for the mainstream Liberal policies of the day. However, it also became clear from these meetings that there were differences between the candidates. Evans addressed the first meeting at Llandovery predominantly using the Welsh language, which invited a contrast with his opponent's limited knowledge of Welsh. As a result, Thomas felt compelled at a subsequent meeting at Llandeilo to appeal that his lack of fluency in Welsh should not be held to support his opponent. Evans placed himself firmly in the radical camp, supporting Home Rule. emphasizing his prominent role as a member of Carmarthenshire County Council, and stating that he would follow in the footsteps of Mabon, David Randell and Tom Ellis. Thomas, in contrast expressed himself to be an opponent of Home Rule for Wales.